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t 

DARWIN,  AND  AFTER  DARWIN 


II 


POST-DARWINIAN    QUESTIONS 
HEREDITY  AND    UTILITY 


BY  THE  SAME  AUTHOR. 


DARWIN,  AND  AFTER  DARWIN.  An  Exposition  of  the 
Darwinian  Theory  and  a  Discussion  of  Post-Darwinian 
Questions. 

I.  The  Darwinian  Theory.  With  Portrait  of  Darwin. 
460  pages.     125  illustrations.    Cloth,  fj.oo. 

a.  Post-Darwinian  Questions.  Edited  by  Prof.  C. 
Lloyd  Morgan.  With  Portrait  of  G.  J.  Romanes. 
338  pages.     Cloth,  51.50. 

3.  Post-Darwinian  Questions.     Isolation  and  Phy- 
siological Selection.    Edited   by  Prof.  C.  Lloyd 
Morgan.     With  Portrait  of  Mr.  J.  T.  Gulick.     i8i 
pages.    Cloth,  fi.oo. 
All  three  volumes  together,  $4.00  net. 

AN   EXAMINATION  OF  WEISMANNISM.    With   Portrait 

of  Weisniann.    236  pages.    Cloth,  $1.00. 
THOUGHTS  ON  RELIGION.  Edited  by  Charles  Gore,  M.A., 

Canon  of  Westminster.    Third  Edition.    184  pages.   Cloth, 

gilt  top,  $1.25. 


THE  OPEN  COURT  PUBLISHING  COMPANY. 
324  Dearborn  Street,  Chicago. 


\       * 


I 


A^} 


DARWIN,  AND  AFT1:K  DARWIN 


AX  EXPOS  IT/OX  OF  THE  DARWIXlAX  THEORY 

AXD  A  niSCUSSIOX  OF 

POST-DA R IVIXIAX  QUES TIOXS 


nv  THE  I.ATK 


GEORGE  JOHN  ROMANES,   M.A.,  LL.D.,  F.R.S. 

Honorary  l-clUnv  of  ConvilU  iind  Cuius  College,  CambriJf^c 


II 

POST-DARWINIAN  QUESTIONS 
HEREDITY  AND  UTILITY 


SECOND  EDITION. 

V  7. 


Chicago 

THE    OPEN   COURT    PUBLISHING  COMPANY 

1897 


CHAPTER  I.   COPVRIGHTEI)  HY 

The  Open  Court  Publishing  Co. 

CHICAGO,   ILL.,    1895. 


*•    ''•    DONNELLEV  &  SONS  CO.   CHICAGO 


PREFACE 


-•♦- 


As  its  sub-title  announces,  the  prrsent  volume  is 
mainly  devoted  to  a  consideration  of  those  Post- 
Darwinian  Theories  which  involve  fundamental 
questions  of  Heredity  and  Utility. 

As  regards  Heredity,  I  have  restricted  the  discussion 
almost  exclusively  to  Professor  Weismann's  views, 
partly  because  he  is  at  present  by  far  the  most  im- 
portant writer  upon  this  subject,  and  partly  because 
his  views  with  regard  to  it  raise  witli  most  distinctness 
the  issue  which  lies  at  the  base  of  all  Post-Darwinian 
speculation  touching  this  subject— the  issue  as  to  the 
inheritance  or  non-inheritance  of  acquired  characters. 

My  examination  of  the  Utility  question  may  well 
seem  to  the  general  reader  needlessly  elaborate ;  for 
to  such  a  re.ader  it  can  scarcely  fail  to  appear  that 
the  doctrine  which  I  am  assailing  has  been  broken 
to  fragments  long  before  the  criticism  has  drawn  to 
a  close.  But  from  my  previous  experience  of  the 
hardness  with  which  this  fallacious  doctrine  dies, 
I  do  not  deem  it  safe  to  allow  even  one  fragment  of 
it  to  remain,  lest,  hydra-like,  it  should  re-develop  into 

a  3 


yi 


Preface, 


its  former  proportions.  And  I  can  scarcely  think 
that  naturah'sts  who  know  the  growing  prevalence 
of  the  doctrine,  and  who  may  have  followed  the  issues 
of  previous  discussions  with  regard  to  it,  will  accuse 
me  of  being  more  over-zealous  in  my  attempt  to  make 
a  full  end  thereof. 

One  more  remark.  It  is  a  misfortune  attending 
the  aim  and  scope  of  Part  II  that  they  bring  me 
into  frequent  discord  with  one  or  other  of  the  most 
eminent  of  Post-Darwinian  writers — especially  with 
Mr.  Wallace.  But  such  is  the  case  only  because 
the  subject-matter  of  this  volume  is  ?ivowedly  re- 
stricted to  debateable  topics,  and  because  I  choose 
those  naturalists  who  are  deservedly  held  in  most 
esteem  to  act  spokesmen  on  behalf  of  such  Post- 
Darwinian  views  as  appear  to  me  doubtful  or  erro- 
neous. Obviously,  however,  differences  of  opinion 
on  particular  points  ought  not  to  be  taken  as  imply- 
ing any  failure  on  my  part  to  recognize  the  general 
scientific  authority  of  these  men,  or  any  inability 
to  appreciate  their  labours  in  the  varied  fields  of 
Biology. 


G.  J.  R. 


C-tRisT  Church,  Oxford. 


NOTE 


Some  time  before  his  death  Mr.  Romanes  decided 
to  pubh'sh  those  sections  of  his  work  which  deal  with 
Heredity  and  Utility,  as  a  separate  volume,  leaving 
Isolation  and  Physiological  Selection  for  the  third  and 
concluding  part  of  Darwin,  and  after  Darwin. 

Most  of  the  matter  contained  in  this  part  was 
already  in  type,  but  was  not  finally  corrected  for  the 
press.  The  alterations  made  therein  are  for  the  most 
part  verbal. 

Chapter  IV  was  type-written  ;  in  it,  too,  no  altera- 
tions of  any  moment  have  been  made. 

For  Chapters  V  and  VI  there  were  notes  and  iso- 
lated paragraphs  not  yet  arranged.  I  had  promised 
during  his  life  to  write  for  Mr.  Romanes  Chapter  V 
on  the  basis  of  these  notes,  extending  it  in  such  ways 
as  seemed  to  be  desirable.  In  that  case  it  would 
have  been  revised  and  amended  by  the  author  ana 
received  his  final  sanction.  Death  annulled  this 
friendly  compact;  and  since,  had  I  written  the 
chapter  myself,  it  could  not  receive  that  imprimatur 
which  would  have  given  its  chief  value,  I  have  decided 


viif 


Note. 


to  arrange  the  material  that  passed  into  my  hands 
without  adding  anything  of  importance  thereto.  The 
substance  of  Chapters  V  and  VI  is  theretbre  entirely 
the  author's  :  even  the  phraseology  is  his ;  the  arrange- 
ment only  is  by  another  hand. 

Such  parts  of  the  Preface  as  more  particularly 
refer  to  Isolation  and  Physiological  Selection  are 
reserved  for  publication  in  Part  ill.  A  year  or  more 
must  elapse  before  that  part  will  be  ready  for 
publication. 

Mr.  F.  Howard  Collins  has,  as  a  kindly  tribute  to 
the  memory  of  the  author,  read  through  the  proofs. 
Messrs.  F.  Darwin,  F.  Galton,  H.  Seebohm,  and  others, 
have  rendered  incidental  assistance.  After  much 
search  I  am  unable  to  give  the  references  to  one  or 
two  passages. 

I  have  allowed  a  too  flattering  reference  to  myself 
to  stand,  in  accordance  with  a  particular  injunction  of 
Mr.  Romanes  given  shortly  before  that  sad  day  on 
which  he  died,  leaving  many  to  mourn  the  loss  of 
a  personal  friend  most  bright,  lovable,  and  generous- 
hearted,  and  thousands  to  regret  that  the  hand  which 
had  written  so  much  for  them  would  write  for  them 
no  more. 

C  Ll.  M. 

University  College,  Bristol, 
April,  1894. 


CONTENTS 


CHAPTER  I. 

Introductory:  The  Darwinism  of  Darwin  and  of  the 
Post-Darwinian  Schools 


PAGI 
I 


CHAPTER   II. 
Characters  as  Hereditary  and  Acquired  {Preliminary^      39 

CHAPTER   III. 

Characters  as  Hereditary  and  Acquired  {Continued). 

A.  Indirect  evidence  in  favour  of  the  Inheritance  of  Ac- 

quired Characters 

•         •         •        •         » 

B.  Inhentcd  effects  of  Use  and  of  Disuse  . 


60 
95 


103 


CHAPTER    IV. 

Characters  as  Hereditary  and  Acquired  {Continued). 
C.  Exprimenial  evidence  in  favour  of  the  Inheritance  of 
Acquired  Characters         .... 

CHAPTER   V. 

Characters  as  Hereditary  and  Acquired  {Continued). 
A.  and  B.  Direct  and  L^direct  Evidence  in  favour  of  the 

^on-inheriiance  of  Acquired  Characters    .         .         .     i-, 
C.  Experimental  Evidence  as  to  the  Non  inheritance  of 
Acquired  Characters 

'4* 


Contents, 


CHAPTER  VI. 

MOS 

Characters  as   Hereditary  and  Acquired  {Conclusion)  150 

CHAPTER  VII. 
Characters  as  Adaptive  and  Specific       .       .       •       .159 

CHAPTER  VIII. 

Characters  as  Adaptive  and  Specific  {Continued). 

I.  Climate aoo 

II.  Food 217 

III.  Sexual  Selection 219 

IV.  Isolation 223 

V.  Laivs  of  Growth 226 

CHAPTER  IX. 

Characters  as  Adaptive  and  Specific  {Continued)  .       .  aa8 

CHAPTER   X. 

Characters  as  Adaptive  and  Specific  {Concluded)  .        .  251 

Summary 274 

Appendix  I.  On  Panmixia 29^ 

Appendix  II.  On  Characters  as  Adaptive  and  Specific  .  307 

Note  A  to  Page  57 333 

Note  B  to  Page  89 337 


LIST    OF    ILLUSTRATIONS 


Portrait  of  George  John  Ro„.anes        ....        prontUpZ 

Diagram  of  Prof.  Weismann's  Theories 

*        *         '         •         •      43 
Fig.  I.  Guinea  pigs,  showing  gangrene  of  ears  due  to  injury  of 

restiform  bodies  ...  o 

•        •        •        •     lis 


Fig.  a.  Old  Irish  Pig  (after  Richardson)      . 
Fig.  3.  Skulls  of  Niata  Ox  and  of  Wild  White  Ox 
F IG.  4.  Lower  teeth  of  Orang  (after  Tomes) 


188 
192 
367 


I 


DARWIN,  AND  AFTER  DARWIN. 


CHAPTER  I. 

Introductory:  The  Darwinism  of  Darwin, 
AND  of  the  Post-Darwinian  Schools. 

It  is  desirable  to  open  this  volume  of  the  treatise 
on  Darwin  and  after  Darivin  by  taking  a  brief 
survey  of  the  general  theory  of  descent,  first,  as  this 
was  held  by  Darwin  himself,  and  next,  as  it  is  now 
held  by  the  several  divergent  schools  of  thought  which 
have  arisen  since  Darwin's  death. 

The  most  important  of  the  questions  in  debate  is 
one  which  I  have  already  had  occasion  to  mention, 
while  dealing,  in  historical  order,  with  the  objections 
that  were  brought  against  the  theory  of  natural 
selection  during  the  life-time  of  Darwin  ^.  Here,  how- 
ever, we  must  consider  it  somewhat  more  in  detail, 
and  justify  by  quotation  what  was  previously  said 
regarding  the  very  definite  nature  of  his  utterances 
upon  the  matter.  This  question  is  whether  natural 
selection  has  been  the  sole,  or  but  the  main,  cause 
of  organic  evolution. 

»  Part  I,  pp.  353-356. 
II.  B 


2  Danvin,  and  after  Darwin, 

Must  we  regard  survival  of  the  fittest  as  the  one 
and  only  principle  which  has  been  concerned  in  the 
progressive  modification  of  living  forms,  or  are  we  to 
suppose  that  this  great  and  leading  principle  has  been 
assisted  by  other  and  subordinate  principles,  without 
the  co-operation  of  which  the  results,  as  presented  in 
the  animal  and  vegetable  kingdoms,  could  not  have 
been  effected?  Now  Darwin's  answer  to  this  question 
was  distinct  and  unequivocal.  He  stoutly  resisted 
the  doctrine  that  natural  selection  was  to  be  regarded 
as  the  only  cause  of  organic  evolution.  On  the  other 
hand,  this  opinion  was — and  still  continues  to  be — 
persistently  maintained  by  Mr.  Wallace ;  and  it  con- 
stitutes the  source  of  all  the  differences  between  his 
views  and  those  of  Darwin.  Moreover,  up  to  the  time 
of  Darwin's  death,  Mr.  Wallace  was  absolutely  alone 
in  maintaining  this  opinion  :  the  whole  body  of 
scientific  thought  throughout  the  world  being  against 
him ;  for  it  was  deemed  improbable  that,  in  the 
enormously  complex  and  endlessly  varied  processes 
of  organic  evolution,  only  a  single  principle  should  be 
everywhere  and  exclusively  concerned  ^  But  since 
Darwin's  death  there  has  been  a  great  revolution  of 
biological  thought  in  favour  of  Mr.  Wallace's  opinion. 
And  the  reason  for  this  revolution  has  been,  that 
his  doctrine  of  natural  selection  as  the  sole  cause 
of  organic  evolution  has  received  the  corroborative 
support  of  Professor  Weismann's  theory  of  heredity — 
which  has  been  more  or  less  cordially  embraced  by 
a  certain  section  of  evolutionists,  and  which  appears  to 
carry  the  doctrine  in  question  as  a  logical  corollary,  so 
far,  at  all  events,  as  adaptive  structures  are  concerned. 
'  CoHtributums  to  the  Theory  of  Natural  Selection,  p.  47. 


y 

o 


Introduction,  3 

Now  in  this  opening  chapter  we  shall  have  to  do 
merely  with  a  setting  forth  of  Darwin's  opinion : 
we  are  not  considering  how  far  that  opinion  ought 
to  be  regarded  as  having  been  in  any  measure  dis- 
placed by  the  results  of  more  recent  progress.  Such, 
then,  being  the  only  matter  which  here  concerns  us, 
I  will  supply  a  few  brief  quotations,  to  show  how 
unequivoci  ly  Darwin  has  stated  his  views.  First, 
we  may  take  what  he  says  upon  the  "  Lamarckian 
factors  ^ ; "  and  next  we  may  consider  what  he  says 
with  regard  to  other  factors,  or,  in  general,  upon 
natural  selection  not  being  the  sole  cause  of  organic 
evolution. 

"  Changed  habits  produce  an  inherited  effect,  as  in  the  period 
of  the  flowering  of  plants  when  transported  from  one  climate  to 
another.  With  animals  the  increased  use  or  disuse  of  parts  has 
had  a  more  marked  influence  ^" 

"  There  can  be  no  doubt,  from  the  facts  given  in  this  chapter, 
that  extremely  slight  changes  in  the  conditions  of  life  sometimes, 
probably  often,  act  in  a  definite  manner  on  our  domesticated 
productions ;  and,  as  the  action  of  changed  conditions  in 
causing  indefinite  variability  is  accumulative,  so  it  may  be  with 
their  definite  action.  Hence  considerable  and  definite  modifi- 
cations of  structure  probably  follow  from  altered  conditions 
acting  during  long  series  of  generations  V* 

"  How,  again,  can  we  explain  the  inherited  effects  of  the  use 
and  disuse  of  particular  organs?    The  domesticated  duck  flies 

'  So  far  as  we  shall  be  concerned  with  them  throughout  this  trea- 
tise, the  "Lamarckian  factors"  consist  in  the  supposed  transmission 
of  acquired  characters,  whether  the  latter  be  due  to  the  direct  influence 
of  external  conditions  of  life  on  the  one  hand,  or  to  the  inherited  effects  of 
use  and  disuse  on  the  other.  For  the  phrase  "  inherited  effects  of  use  and 
disuse,"  I  shall  frequently  employ  the  t  rm  "use-inheritance,"  which  has 
been  coined  by  Mr.  Piatt  Ball  as  a  more  convenient  expression. 

^  Origin  of  Species,  6th  ed.  p.  8. 

'  Variatiim  &c.  2nd  ed.  ii.  p.  380. 

P   2 


Darwin f  and  after  Darwin. 


less  and  walks  more  than  the  wild  duck,  and  its  limb  bones 
have  become  diminished  and  increased  in  a  corresponding 
manner  in  comparison  with  those  of  the  wild  duck.  A  horse  is 
trained  to  certain  paces,  and  the  colt  inherits  similar  consensual 
movements.  T.ie  domesticated  rabbit  becomes  tame  from 
close  confinerr.ent ;  the  dog,  intelligent  from  associating  with 
man ;  the  retriever  is  taught  to  fetch  and  carry ;  and  these 
mental  endowments  and  bodily  powers  are  all  inherited. 
Nothing  in  the  whole  circuit  of  physiology  is  more  wonderful. 
How  can  the  use  or  disuse  of  a  particular  limb  or  of  the  brain 
affect  a  small  aggregate  of  reproductive  cells,  seated  in  a  aistant 
part  of  the  body,  in  such  a  manner  that  the  being  developed 
from  these  crlls  inherits  the  characters  of  either  one  or  both 
parents  ? .  .  .  In  the  chapters  devoted  to  inheritance,  it  was 
shown  that  a  multitude  of  newly  acquired  characters,  whether 
injurious  or  beneficial,  whether  of  the  lowest  or  highest  vital 
importance,  are  often  faithfully  transmitted  \'' 

"When  discussing  special  cases,  Mr.  Mivart  passes  over  the 
effects  of  the  increased  use  and  disuse  of  parts,  which  I  have 
always  maintained  to  be  highly  important,  and  have  treated  in 
my  'Variation  under  Domestication'  at  greater  length  than, 
as  I  believe,  any  other  writer  ".' 

So  much  for  the  matured  opinion  of  Darv/in  touching 
the  validity  of  the  theory  of  use-inheritance.  Turning 
now  to  his  opinion  on  the  question  whether  or  not 
there  are  yet  any  further  factors  concerned  in  the 
process  of  organic  evolution,  I  think  it  will  be  sufficient 
to  quote  a  single  passage  from  the  Origin  of  Species. 
The  first  paragraph  of  the  "  Conclusion  "  is  devoted 
to  a  Hsumd  of  his  views  upon  this  matter,  and  con- 
sists of  the  following  most  emphatic  words. 

"  I  have  now  recapitulated  the  facts  and  considerations  which 
have  thoroughly  convinced  me  that  species  have  been  modified, 
during  a  long  course  of  descent.  This  has  been  effected  chiefly 
through  the  natural  selection  of  numerous  successive,  slight, 

^  Variatum  Si.z.  ii.  p.  367.  '  Origin  of  Specia^  p.  176. 


r 


Introduction. 


favourable  variptions ;  aided  in  an  important  manner  oy  the 
inherited  effects  of  the  use  and  disuse  of  parts ;  and  in  an  un- 
important manner,  that  is  in  reliition  to  adaptive  structures, 
whether  past  or  present,  by  the  direct  action  of  external  con- 
ditions, and  by  variations  which  seem  to  us  in  our  ijjnorance  to 
arise  spontaneously.  It  appears  that  1  formerly  underrated  the 
frequency  and  value  of  these  latter  forms  of  variation,  as  leading 
to  permanent  modifications  of  structure  independently  of  natural 
selection.  Hut  as  my  conclusions  have  lately  been  much  mis- 
represented, and  it  has  been  stated  that  I  attribute  the  modifica- 
tion of  species  exclusively  to  natural  selection,  I  may  be  permitted 
to  i^mark  that  in  the  first  edition  of  this  work,  and  subsequently, 
I  placed  in  a  most  conspicuous  position  -  namely,  at  the  close 
of  the  Introduction— the  following  words  :  *  I  am  convinced  that 
natural  selection  has  been  the  main,  but  not  the  exclusive  means 
of  modification.'  This  has  been  of  no  avail.  Great  is  the 
power  of  steady  misrepresentation  ;  but  the  history  of  science 
shows  that  fortunately  this  power  does  not  long  endure." 

In  the  whole  range  of  Darwin's  writings  there 
cannot  be  found  a  passage  so  strongly  worded  as 
this  :  it  presents  the  only  note  of  bitterness  in  all 
the  thousands  of  pages  which  he  has  published. 
Therefore  I  do  not  think  it  is  necessary  to  supply 
any  further  quotations  for  the  purpose  of  proving 
the  state  of  his  opinion  upon  the  point  in  question. 
But,  be  it  carefully  noted,  from  this  great  or  radical 
difiference  of  opinion  between  the  joint  originators  of 
the  theory  of  natural  selection,  all  their  other  differ- 
ences of  opinion  arise ;  and  seeing  that  since  the 
death  of  Darwin  a  large  number  of  naturalists  have 
gone  over  to  the  side  of  Wallace,  it  seems  desirable 
here  to  state  categorically  what  these  other  or  sequent 
points  of  difference  are.  Without  at  present  discuss- 
ing them,  therefore,  I  will  merely  set  them  out  in  a 
tabular  form,  in  order  that  a  clear  perception  may  be 


6  Danvin,  and  after  Darwin. 

pained  of  their  loj^ical  connexion  witli  this  primary 
point  of  difference. 


h 


The  theory  of  NiUural  Selection 
according  to  Darwin. 


Natural  Selection  has  heen 
the  main  means  of  modifica- 
tion, not  excepting  the  case  of 
Man. 

(a)  Therefore  it  is  a  question 
of  evidence  whether  the  La- 
marckian  factors  have  co- 
operated. 

{b)  Neither  all  species,  nor, 
a  fortiori^  all  specific  char- 
acters, have  been  due  to 
natural  selection. 

[c)  Thus  the  principle  of 
Utility  is  not  of  universal  ap- 
plication, even  where  species 
are  ''oncerned. 

{et)  Thus,  also,  the  sugges- 
tion as  to  Sexual  Selection,  or 
any  other  supplementary  cause 
of  modification,  may  be  enter- 
tained ;  and,  as  in  the  case  of 
the  Lamarckian  factors,  it  is  a 
question  of  evidence  whether, 
or  how  far,  they  have  co- 
operated. 

{e)  No  detriment  arises  to 
the  theory  of  natural  selection 
as  a  theory  of  the  origin  of 
species  by  entertaining  the 
possibility,  or  the  probability, 
of  supplementary  factors. 

(/)  Cross-sterility  in  species 
cannot  possibly  be  due  to 
natural  selection. 


The  theory  of  Natural  Selection 
according  to  Wallace. 


Natural  Selection  has  been 
the  sole  means  of  inotiification, 
excepting  in  the  case  of  Man. 

{a)  Therefore    it    is    ante- 

ce<lcntly  impossible  that  the 
Lamarckian  factors  can  have 
co-operated. 

(b)  Not  only  all  species,  but 
all  specific  characters,  must 
necessarily  'lave  been  due  to 
natural  selection. 

{c)  Thus  the  principle  of 
Utility  must  necessarily  be  of 
uni\ersal  application,  where 
species  are  concerned. 

{d)  Thus,  also,  the  sugges- 
tion as  to  Sexual  Selection,  or 
of  any  other  supplementary 
cause  of  modification,  must  be 
ruled  out ;  and,  as  in  the  case 
of  the  Lamarckian  factors, 
their  co-operation  deemed  im- 
possible. 

{e)  The  possibility — and,  a 
fortiori  the  probability—  of  any 
supplementary  factors  cannot 
be  entertained  without  serious 
detriment  to  the  theory  of 
natural  selection,  as  a  theory 
of  the  origin  of  species. 

(/)  Cross-sterility  in  species 
is  probably  due  to  natural 
selection  ^ 


*  This,  to  the  best  of  my  judgement,  is  the  fairest  extract  that  I  can 
give  of  Mr.  Wallace's  most  recently  published  opinions  oo  the  points  in 


Introduction, 


• 


As  it  will  he  iny  endeavour  in  the  ensuing  chapters 
to  Cf)nsi(lcr  the  rights  and  the  wrongs  of  these  anti- 
tlictical  propositions,  I  may  reserve  furtlicr  quotations 
from  Darwin's  works,  wliich  will  show  that  the  above 
is  a  correct  epitome  of  his  views  as  contrasted  with 
those  of  Wallace  and  the  Neo- Darwinian  school  of 
Weismann.  But  here,  where  the  object  is  merely 
a  statement  of  Darwin's  theory  touching  the  points 
in  which  it  differs  from  those  of  Wallace  and  Weis- 
mann, it  will  be  sufficient  to  set  forth  these  points  of 
difference  in  another  and  somewhat  fuller  form.  So 
far  then  as  we  are  at  present  concerned,  the  fol- 
lowing are  the  matters  of  doctrine  which  have  been 
clearly,  em[)hatically,  repeatedly,  and  uniformly  ex- 
pressed throughout  the  whole  range  of  Darwin's 
writings. 

1 .  That  natural  selection  has  been  the  main  means 
of  modification. 

2.  That,  nevertheless,  it  has  not  been  the  only 
means  ;  but  has  been  supplemented  or  assisted  by  the 
co-operation  of  other  causes. 

3.  That  the  most  *  important "  of  these  other  causes 
has  been  the  inheritance  of  functionally-produced 
modifications  (use-inheritance);  but  this  only  because 
the  transmission  of  such  modifications  to  progeny  must 
always  have  had  immediate  reference  to  adaptive 
ends,  as  distinguished  from  merely  u.seless  change. 

4.  That  there  are  sundry  other  causes  which  lead 


question.  [In  particular  as  rej^aids  {a)  see  Danvinism  pp.  435  6.]  But 
with  regard  to  some  of  them,  his  expression  of  opinion  is  not  always 
consistent,  as  we  shall  find  in  detail  later  on.  Besides,  I  am  here  taking 
Ml.  Wallace  as  representative  of  the  Neo-  Darwinian  school,  one  or  other 
prominent  member  of  which  has  given  emphatic  expression  to  each  of  the 
above  propositions. 


8 


Darwin^  and  after  Darwin. 


to  merely  useless  change — in  particular,  "the  direct 
action  of  external  conditions,  and  variations  which 
seem  to  us  in  our  ignorance  to  arise  spontaneously." 

5.  Hence,  that  the  "  principle  of  utility,"  far  from 
being  of  universal  occurrence  in  the  sphere  of  animate 
nature,  is  only  of  what  may  be  tern  °d  highly  general 
occurrence ;  and,  therefore,  that  certain  other  advocates 
of  the  theory  of  natural  selection  were  mistaken  in 
representing  the  universality  of  this  principle  as 
following  by  way  of  necessary  consequence  from  that 
theory. 

6.  Cross-sterility  in  species  cannot  possibly  be  due 
to  natural  selection  :  but  everywhere  arises  as  a  result 
of  some  physiological  change  having  exclusive  refer- 
ence to  the  sexual  system  —  a  change  which  is 
probably  everywhere  due  to  the  same  cause,  although 
what  this  cause  could  be  Darwin  was  confessedly 
unable  to  suggest. 

Such,  then,  was  the  theory  of  evolution  as  held  by 
Darwin,  so  far  as  the  points  at  present  before  us  are 
concerned.  And,  it  may  now  be  added,  that  the 
longer  he  lived,  and  the  more  he  pondered  these 
points,  the  less  exclusive  was  the  role  which  he  as- 
signed to  natural  selection,  and  the  more  importance 
did  he  attribute  to  the  supplementary  factors  above 
named.  This  admits  of  being  easily  demonstrated 
by  comparing  successive  editions  of  his  works ;  a 
method  adopted  by  Mr.  Herbert  Spencer  in  his 
essay  on  the  Factors  of  Organic  Evolution. 

My  object  in  thus  clearly  defining  Darwin's  attitude 
regarding  these  sundry  points  is  twofold. 

In  the  first  place,  with  regard  to  merely  historical 
accuracy,  it  appears  to  me  undesirable  that  naturalists 


Introduction. 


should  endeavour  to  hide  certain  parts  of  Darwin's 
teaching,  and  give  undue  prominence  to  others.  In 
the  second  place,  it  appears  to  me  still  more  un- 
desirable that  this  should  be  done — as  it  usually  is 
done — for  the  purpose  of  making  it  appear  that 
Darwin's  teaching  did  not  really  differ  very  much 
from  that  of  Wallace  and  Weismann  on  the  important 
points  in  question.  I  myself  believe  that  Darwin's 
judgement  with  regard  to  all  these  points  will 
eventually  prove  more  sound  and  accurate  than 
that  of  any  of  the  recent  would-be  improvers  upon 
his  system ;  but  even  apart  from  this  opinion 
of  my  own.  it  is  undesirable  that  Darwin's  vie  "s 
should  be  misrepresented,  whether  the  misrepre- 
sentation be  due  to  any  unfavourable  bias  against  one 
side  of  his  teaching,  or  to  sheer  carelessness  in  the 
reading  of  his  books.  Yet  the  new  school  of  evo- 
lutionists, to  which  allusion  has  now  so  frequently  been 
made,  speak  of  their  own  modifications  of  Darwin's 
teaching  as  "pure  Darwinism,"  in  contradistinction 
to  what  they  call  "  Lamarckism."  In  other  words, 
they  represent  the  principles  of  "  Darwinism "  as 
standing  in  some  kind  of  opposition  to  those  of 
"  Lamarckism  "  :  the  Darwinian  principle  of  natural 
selection,  they  think,  is  in  itself  enough  to  account  for 
all  the  facts  of  adaptation  in  organic  nature.  There- 
fore they  are  eager  to  dispense  with  the  Lamarckian 
principle  of  the  inherited  effects  of  use  and  disuse, 
together  with  the  direct  influence  of  external  conditions 
of  life,  and  all  or  any  other  causes  of  modification  which 
either  have  been,  or  in  the  future  may  po.ssibly  be, 
suggested.  Now,  of  course,  there  is  no  reason  why 
any  one  should  not  hold  these  or  any  other  opinions 


I: 


lo         Darwin y  and  after  Darwin, 

to  which  his  own  independent  study  of  natural  science 
may  lead  him ;  but  it  appears  to  me  that  there  is 
the  very  strongest  reason  why  any  one  v/ho  deviates 
from  the  carefully  formed  opinions  of  such  a  man 
as  Darwin,  should  above  all  things  be  careful  to 
be  absolutely  fair  in  his  representations  of  them ; 
he  should  be  scrupulously  jealous,  so  to  speak,  of 
not  letting  it  appear  that  he  is  unjustifiably  throwing 
over  his  own  opinions  the  authority  of  Darwin's 
name. 

But  in  the  present  case,  as  we  have  seen,  not  only 
do  the  Neo-Darwinians  strain  the  teachings  of  Dar- 
win ;  they  positively  reverse  those  teachings — repre- 
senting as  anti-Darwinian  the  whole  oi  one  side  of 
Darwin's  system,  and  calling  those  who  continue  to 
accept  that  system  in  its  entirety  by  the  name 
"  Lamarckians."  I  know  it  is  sometimes  said  by 
members  of  this  school,  that  in  his  utilization  of 
Lamarckian  principles  as  accessory  to  his  own, 
Darwin  was  actuated  by  motives  of  "generosity."  But 
a  more  preposterous  suggestion  could  not  well  be 
made.  We  may  fearlessly  challenge  any  one  who 
speaks  or  writes  in  such  a  way,  to  show  any  other 
instance  where  Darwin's  great  generosity  of  dis- 
position had  the  effect  of  influencing  by  one  hair's 
breadth  his  still  greater  loyalty  to  truth.  Moreover, 
and  with  special  regard  to  this  particular  case,  I 
would  point  out  that  in  no  one  of  his  many  allu- 
sions to,  and  often  lengthy  dicussions  of,  these  so- 
called  Lamarckian  principles,  does  he  ever  once 
introduce  the  name  of  Lamarck ;  while,  on  the  other 
hand,  in  the  only  places  where  he  does  so— whether 
in  his  books   or  in  his  now  published  letters— he 


t 


Introduction, 


II 


science 
there  is 
deviates 

a  man 
reful  to 

them ; 
>eak,  of 
irowing 
)a:win's 

ot  only 
)f  Dar- 
-repre- 
side  of 
inue  to 

name 
aid  by 
ion    of 

own, 
'  But 
ell  be 
e  who 

other 

f   dis- 

hair's 

cover, 

Fase,  I 

allu- 
se  so- 

once 

other 

lether 

s— he 


does  so  in  order  to  express  an  almost  contemptuous 
dissatisfaction,  and  a  total  absence  of  obligation. 
Hence,  having  regard  to  the  "generosity"  with 
which  he  always  acknowledged  obligations,  there 
can  be  no  reasonable  doubt  that  Darwin  was  not  in 
the  smallest  degree  influenced  by  the  speculative 
writings  of  Lamarck  ;  or  that,  even  if  Lamarck  had 
never  lived,  the  Origin  of  Species  would  have  differed 
in  any  single  particular  from  the  form  in  which  it 
now  stands.  Finally,  it  must  not  be  forgotten  that 
Darwin's  acceptance  of  the  theory  of  use- inherit- 
ance was  vitally  essential  to  his  theory  of  Pangenesis 
— that  'beloved  child"  over  which  he  had  "thought 
so  much  as  to  have  lost  all  power  of  judging  it^." 

What  has  just  been  said  touching  the  relations 
between  Darwin's  theory  and  that  of  Lamarck, 
applies  with  equal  force  to  the  relations  between 
Darwin's  theory  and  any  other  theory  appertain- 
ing to  evolution  which  has  already  been,  or  may 
hereafter  be.  propounded.  Yet  so  greatly  have 
some  of  the  Neo-Darwinians  misunderstood  the  teach- 
ings of  Darwin,  that  they  represent  as  "Darwinian 
heresy"  any  suggestions  in  the  way  of  factors  "supple- 
mentary to,"  or  "co-operative  with"  natural  selection. 
Of  course,  if  these  naturalists  were  to  avow  themselves 
followers  of  Wallace,  instead  of  followers  of  Darwin, 
they  would  be  perfectly  justified  in  repudiating  any 
such  suggestions  as,  ipso  facto,  heretical.  But,  as  we 
have  now  seen,  through  all  his  life  Darwin  differed 
from  Wallace  with  regard  to  this  very  point ;  and 
therefore,  unlike  Wallace,  he  was  always  ready  to  en- 
tertain "  additional  suggestions  "  regarding  the  causes 
'  Life  and  Letters,  vol.  iii.  pp.  73  and  75. 


la 


Darwin^  and  after  Darwin. 


\ 
J 


of  organic  evolution — several  of  which,  indeed,  he 
himself  supplied.  Hence  we  arrive  at  this  curious 
state  of  matters.  Those  biologists  who  of  late  years 
have  been  led  by  Weismann  to  adopt  the  opinions  of 
Wallace,  represent  as  anti-Darwinian  the  opinions  of 
other  biologists  who  still  adhere  to  the  unadulterated 
doctrines  of  Darwin.  Weismann's  Essays  on  Heredity 
(which  argue  that  natural  selection  is  the  only  pos- 
sible cause  of  adaptive  modification)  and  Wallace's 
work  on  Darwinism  (which  in  all  the  respects 
where  any  charge  of  "  heresy  "  is  concerned  directly 
contradicts  the  doctrine  of  Darwin) — these  are  the 
writings  which  are  now  habitually  represented  by  the 
Neo-Darwinians  as  setting  forth  the  views  of 
Darwin  in  their  '  pure "  form.  The  result  is  that, 
both  in  conversation  and  in  the  press,  we  habitually 
meet  with  complete  inversions  of  the  truth,  which 
show  the  state  of  confusion  into  which  a  very  simple 
matter  has  been  wrought  by  the  eagerness  of  certain 
naturalists  to  identify  the  views  of  Darwin  with  those 
of  Wallace  and  Weismann.  But  we  may  easily 
escape  this  confusion,  if  we  remember  that  wherever 
in  the  writings  of  these  naturalists  there  occur  such 
phrases  as  "pure  Darwinism"  we  are  to  understand 
pure  Wallaceism,  or  the  pure  theory  of  natural 
selection  to  the  exclusion  of  any  supplementary 
theory.  Therefore  it  is  that  for  the  sake  of  clearness 
I  coined,  several  years  ago,  the  terms  "  Neo-Darwin- 
ian  "  and  "  Ultra-Darwinian  "  whereby  to  designate 
the  school  in  question. 


So  much,  then,  for  the  Darwinism  of  Darwin,  as 
contrasted  with  the  Darwinism  of  Wallace,  or,  what 


« 


Introduction. 


13 


is  the  same  thing,  of  the  Neo-Danvinian  school  of 
Weismann.  Next  we  may  turn,  by  way  of  antithesis, 
to  the  so-called  "  Neo-Lamarckian "  school  of  the 
United  States.  For,  by  a  curious  irony  of  fate,  while 
the  Neo-D^rv/inian  school  is  in  Europe  seeking  to 
out-Darwin  Darwin  by  assigning  an  exclusive  pre- 
rogative to  natural  selection  in  both  kingdoms  of 
animate  nature,  the  Neo-Lamarckian  school  is  in 
America  endeavouring  to  reform  Darwinism  in 
precisely  the  opposite  direction — viz.  by  transferring 
the  sovereignty  from  natural  selection  to  the 
principles  of  Lamarck.  Without  denying  to  natural 
selection  a  more  or  less  important  part  in  the  process 
of  organic  evolution,  members  of  this  school  believe 
that  much  greater  importance  ought  to  be  assigned 
to  the  inherited  effects  of  use  and  disuse  than  was 
assigned  to  these  agencies  by  Darwin.  Perhaps 
this  noteworthy  state  of  affairs,  within  a  decade  of 
Darwin's  death,  may  lead  us  to  anticipate  that  his 
judgement — standing,  as  it  does,  between  these  two 
extremes — will  eventually  prove  the  most  accurate 
of  all,  with  respect  to  the  relative  importance  of 
these  factors  of  evolution.  But,  be  this  as  it  may, 
I  must  now  offer  a  few  remarks  upon  the  present 
position  of  the  matter. 

In  the  first  place,  to  any  one  who  (with  Darwin  and 
against  Weismann)  admits  not  only  the  abstract  pos- 
sibility, but  an  actual  working,  of  the  Lamarckian 
factors,  it  becomes  difficult  to  determine,  even 
approximately,  the  degrees  of  value  which  ought  to 
be  ascribed  to  them  and  to  natural  selection  respec- 
tively. For,  since  the  results  are  in  both  cases  identical 
in  kind  (as,  adaptive  changes  of  organic  types),  where 


14  Darwin^  and  after  Darwin. 

both  sets  of  causes  are  supposed  to  be  in  operation 
together,  we  have  no  means  of  estimating  the  relative 
shares  which  they  have  had  in  bringing  about  these 
results.  Of  course  there  are  large  numbers  of  cases 
where  it  cannot  possibly  be  supposed  that  the 
Lamarckian  factors  have  taken  any  part  at  all  in  pro- 
ducing the  observed  effects ;  and  therefore  in  such  cases 
there  is  almost  full  agreement  among  evolutionists  in 
theoretically  ascribing  such  effects  to  the  exclusive 
agency  of  natural  selection.  Of  such,  for  instance,  are 
the  facts  of  protective  colouring,  of  mimicry,  of  the 
growth  of  parts  which,  although  useful,  are  never 
active  (e.  g.  shells  of  mollusks,  hard  coverings  of  seeds), 
and  so  on.  But  in  the  majority  of  cases  where 
adaptive  structures  are  concerned,  there  is  no  means 
of  discriminating  between  the  influences  of  the 
Lamarckian  and  the  Darwinian  factors.  Conse- 
quently, if  by  the  Neo-Lamarckian  school  we  under- 
stand all  those  naturalists  who  assign  any  higher 
importance  to  the  Lamarckian  factors  than  was 
assigned  to  them  by  Darwin,  we  may  observe  that 
members  of  this  school  differ  very  greatly  among 
themselves  as  to  the  degree  of  importance  that  ought 
to  be  assigned.  On  the  one  hand  we  have,  in  Europe, 
Giard,  Perrier,  and  Eimer,  who  stand  nearer  to  Dar- 
win than  do  a  number  of  the  American  representatives 
— of  whom  the  most  prominent  are  Cope,  Osborn, 
Packard,  Hyatt,  Brooks,  Ryder,  and  Dall.  The  most 
extreme  of  these  is  Professor  Cope,  whose  collection 
of  essays  entitled  The  Origin  of  the  Fittest,  as  well  as 
his  more  recent  and  elaborate  monograph  on  The 
Development  of  the  Hard  Parts  of  the  Mammalia, 
represent  what  appears  even  to  some  other  members 


Introduction. 


15 


of  his  school  an  extravagant  estimate  of  the  impor- 
tance of  Lamarckian  principles. 

But  the  most  novel,  and  in  many  respects  the 
most  remarkable  school  of  what  may  be  termed 
Anti-selectionists  is  one  which  is  now  (1894)  rapidly 
increasing  both  in  numbers  and  in  weight,  not  only 
in  the  New  World,  but  also  in  Germany,  and  to  a 
lesser  extent,  in  Great  Britain. 

This  school,  without  being  either  Lamarckian  or 
Darwinian  (for  its  individual  members  differ  widely 
from  one  another  in  these  respects)  maintains  a 
principle  which  it  deems  of  more  importance  than 
either  use-inheritance  or  natural  selection.  This  prin- 
ciple it  calls  Self-adaptation.  It  is  chiefly  botanists 
who  constitute  this  school,  and  its  principal  representa- 
tives, in  regard  to  authority,  are  Sachs,  Pfefifer  and 
Henslow. 

Apart  from  topics  which  are  to  be  dealt  with  in 
subsequent  chapters,  the  only  matters  of  much  impor- 
tance which  have  been  raised  in  the  Post- Darwinian 
period  are  those  presented  by  the  theories  of  Geddes, 
Cope.  Hyatt,  and  others,  and  certain  more  or  less 
novel  ideas  set  forth  in  Wallace's  Darzvinism. 

Mr.  Geddes  has  propounded  a  new  theory  of  the 
origin  of  species,  which  in  his  judgement  supersedes  to 
a  large  extent  the  theory  of  natural  selection.  He  has 
also,  in  conjunction  with  Mr.  Thomson,  propounded 
a  theory  of  the  origin  of  sex.  For  mj'  own  part,  I 
cannot  see  that  these  views  embody  any  principles 
or  suggestions  of  a  sufficiently  definite  kind  to 
constitute  them  theories  at  all.  In  this  respect  the 
views  of  Mr.  Geddes  resemble  those  of  Professors 
Cope,  Hyatt,  and  others,  on  what  they  term  "the 


x6 


Darwin,  and  after  Darwin, 


law  of  acceleration  and  retardation."  In  all  these 
cases,  so  far  as  I  can  see,  the  so-called  explanations 
are  not  in  fact  any  explanations ;  but  either  a  mere 
re-statement  of  the  facts,  or  else  an  enunciation  of 
more  or  less  meaningless  propositions.  Thus,  when 
it  is  said  that  the  evolution  of  any  given  type  has 
been  due  to  the  "  acceleration  of  growth-force  "  with 
respect  to  some  structures,  and  the  "retardation  of 
growth-force"  with  respect  to  others,  it  appears 
evident  that  we  have  not  any  real  explanation  in  terms 
of  causality;  we  have  only  the  form  of  an  explanation 
in  the  terms  of  a  proposition.  All  that  has  been  done 
is  to  express  the  fact  of  evolution  in  somewhat  obscure 
phraseology,  since  the  very  thing  we  want  to  know 
about  this  fact  is — What  are  the  causes  of  it  as  a  fact, 
or  the  reasons  which  have  led  to  the  increase  of  some 
of  the  parts  of  any  given  type,  and  the  concomitant 
decrease  of  others  ?  It  is  merely  the  facts  themselves 
that  are  again  presented  by  saying  that  the  develop- 
ment has  been  in  the  one  case  accelerated,  while  in 
the  other  it  has  been  retarded  *. 

So  much  for  what  may  be  termed  this  New 
World  theory  of  the  origin  of  species:  it  is  a  mere 
re-statement  of  the  facts.     Mr.  Geddes'  theory,  on  the 


m 


*  Take,  for  example,  the  following,  which  is  a  fair  epitome  of  the 
whole: — "I  believe  that  this  is  the  simplest  mode  of  stating  and 
explaining  the  law  of  variation ;  that  some  forms  acquire  something 
which  their  parents  did  not  possess;  and  that  those  which  acquire 
something  additional  have  to  pass  through  more  numerous  stages  than 
their  ancestors ;  and  those  which  lose  something  pass  through  fewer 
stages  than  their  ancestors ;  and  these  processes  are  expressed  by  the 
terms  "acceleration  "  and  "retardation  "  {Origin  of  the  Fittest,  pp.  125, 
226,  and  297).  Even  if  this  be  "the  simplest  mode  of  stating  the  law 
of  variation,"  it  obviously  does  nothing  in  the  way  of  explaining  the 
law. 


Introduction, 


17 


-■>■' 

I 

I 


I 


other  hand,  although  more  than  a  mere  re-statcmcnt 
of  the  facts,  appears  to  me  too  vague  to  be  of  any 
explanatory  service.  His  view  is  that  organic  evolu- 
tion has  everywhere  depended  upon  an  antagonism, 
within  the  limits  of  the  same  organism,  between  the 
processes  of  nutrition  and  those  of  reproduction.  But 
although  he  is  thus  able  hypothetically  to  explain 
certain  facts — such  as  the  shortening  of  a  flower-spike 
into  a  composite  flower — the  suggestion  is  obviously 
inadequate  to  meet,  even  hypothetically,  most  of  the 
facts  of  organic  evolution,  and  especially  the  develop- 
ment of  adaptive  structures.  Therefore,  it  seems  to  me, 
we  may  dismiss  it  even  as  regards  the  comparatively 
few  facts  which  it  might  conceivably  explain — seeing 
that  these  same  facts  may  be  equally  well  explained 
by  the  causes  which  are  already  known  to  operate 
in  other  cases.  For  it  is  the  business  of  natural 
selection  to  ensure  that  there  shall  nowhere  be  any 
needless  expenditure  of  vital  energy,  and,  conse- 
quently, that  everywhere  the  balance  between  nutrition 
and  reproduction  shall  be  most  profitably  adjusted. 

Similarly  with  respect  to  the  theory  of  the  Origin 
of  Sex,  I  am  unable  to  perceive  even  this  much  of 
scientific  relevancy.  As  stated  by  its  authors  the 
theory  is,  that  the  female  is  everywhere  "anabolic," 
as  compared  with  the  male,  which  is  "  katabolic."  By 
anabolic  is  meant  comparative  inactivity  of  proto- 
plasmic change  due  to  a  nutritive  winding  up  of 
molecular  constitution,  while  by  katabolic  is  meant 
the  opposite  condition  of  comparative  activity  due  to 
a  dynamic  running  down  of  molecular  constitution. 
How,  then,  can  the  origin  of  sex  be  explained,  or  the 
causes  which  led  to  the  differentiation  of  the  sexes  be 

II.  c 


i8 


Darwin ^  and  after  Darwin. 


shown,  by  saying  that  the  one  sex  is  anabolic  and  the 
other  katabolic  ?  In  so  far  as  these  verbal  statements 
serve  to  express  what  is  said  to  be  a  general  fact — 
namely,  that  the  female  sexual  elements  are  less 
mobile  than  the  male — they  merely  serve  to  re-state 
this  general  fact  in  terminology  which,  as  the  authors 
themselves  observe,  is  "  unquestionably  ugly."  But 
in  so  far  as  any  question  of  origin  or  causality  is  con- 
cerned, it  appears  to  me  that  there  is  absolutely  no 
meaning  in  such  statements  They  belong  to  the 
order  of  merely  formal  explanations,  as  when  it  is  said 
that  the  toxic  qualities  of  morphia  are  due  to  this 
drug  possessing  a  soporific  character. 

Much  *:he  same,  in  my  opinion,  has  to  be  said  of 
the  Rev.  G.  Henslow's  theory  of  the  origin  of  species 
by  what  he  terms  "self-adaptation."  Stated  briefly 
his  view  is  that  there  is  no  sufficient  evidence  of 
natural  selection  as  a  vera  causa,  while  there  is  very 
abundant  evidence  of  adjustments  occurring  without 
it,  first  in  individual  organisms,  and  next,  by  inherit- 
ance of  acquired  characters,  in  species.  Now,  much 
that  he  says  in  criticism  of  th'  selection  theory  is  of 
considerable  interest  as  such ;  but  when  we  pass 
from  the  critical  to  the  constructive  portions  of  his 
books  and  papers,  we  again  meet  with  the  want  of 
clearness  in  thought  between  a  statement  of  facts 
in  terms  of  a  proposition,  and  an  explanation  of 
them  in  those  of  causality.  Indeed,  I  understand 
from  private  correspondence,  that  Mr.  Henslow  him- 
self admits  the  validity  of  this  criticism ;  for  in 
answer  to  my  questions, — "  How  does  Self-adapta- 
tion work  in  each  case,  and  why  should  protoplasm 
be  able  to  adapt  itself  into  the  millions  of  diverse 


Introduction. 


19 


■ :) 


I 


mechanisms  in  nature?  " — he  writes,  "Self-adnptation 
does  not  profess  to  be  a  vera  causa  at  all :  for  the 
true  causes  of  variation  can  only  be  found  in  the 
answer  to  your  [above]  questions,  and  I  must  say 
at  once,  these  questions  cannot  he  answered"  That 
is,  they  cannot  be  answered  on  the  hyi^othesis  of 
self-adaptation,  which  is  therefore  a  statement  of 
the  facts  of  adaptation  as  distinc^uished  from  an 
exi)lanation  of  them.  Nevertheless,  two  thiiij^s  have 
here  to  be  noted.  In  the  first  place,  the  statement 
of  facts  which  Mr.  Henslow  has  collected  is  of  con- 
siderable theoretical  importance  as  tending  to  show 
that  there  are  probably  causes  of  an  internal  kind 
(i.e.  other  than  natural  selection)  which  have  been 
largely  concerned  in  the  adaptive  modification  of 
plants.  And,  in  the  second  place,  it  is  not  quite  true 
that  the  theory  of  self-adaptation  is,  as  its  author 
says  in  the  sentences  above  quoted  a  mere  statement 
of  the  facts  of  adaptation,  without  any  attempt  at 
explaining  their  causes.  For  in  his  published  words 
he  does  attempt  to  do  so^  And.  although  I  think 
his  attempt  is  a  conspicuous  failure,  I  ought  in  fair- 
ness to  give  examples  of  it.  His  books  are  almost 
exclusively  concerned  in  an  application  of  his  theory 
to  the  mechanisms  of  flowers  for  securing  their  own 
fertilization.  These  mechanisms  he  ascribes,  in  the 
case  of  entomophylous  flowers,  to  the  "  thrusts," 
"strains,"  and  other  '*  irritations "  supplied  to  the 
flowers  by  their  insect  visitors,  and  consequent  "reac- 
tions "  of  the  vegetable  "  protoplasm."  But  no 
attempt   is    made  to   show  why   these   *'  reactions " 

'  Floral  structures  (Intemat.  Sc.  Ser.  Ixiv.  1888):   The  Making  of 
Flowers  (Romance  of  Science  Ser.  1891) ;  and  Linn.  Soc.  Papers  1893-4. 

C   % 


20  Darwin,  and  after  Darwin. 


should  be  of  an  adaptive  kind,  so  as  to  build  up 
the  millions  of  diverse  and  often  elaborate  mechanisms 
in  question — including  not  only  forms  and  move- 
ments, but  also  colours,  odours,  and  secretions.  For 
my  own  part  I  confess  that,  even  granting'  to  an 
ultra-Lamarci<ian  extent  the  inheritance  of  acquired 
characters,  I  could  conceive  of  "self-adaptation"  alone 
producing  all  such  innumeral)le  and  diversified  adjust- 
ments only  after  seeing,  with  Cardinal  Newman,  an 
angel  in  every  flower.  Yet  Mr.  Henslow  somewhat 
vehemently  repudiates  any  association  between  his 
theory  and  that  of  teleology. 

On  the  whole,  then,  I  regard  all  the  works  which 
are  here  classed  together  (those  by  Cope,  Geddes, 
and  Henslow),  as  resembling  one  another  both  in 
their  merits  and  defects.  Their  common  merits  lie 
in  their  erudition  and  much  of  their  criticism,  while 
their  common  defects  consist  on  the  one  hand  in  not 
sufficiently  distinguishing  between  mere  statements 
and  real  explanations  of  facts,  and,  on  the  other,  in 
not  perceiving  that  *^he  theories  severally  suggested 
as  substitutes  for  tbuw  of  natural  selection,  even  if 
they  be  granted  true,  could  be  accepted  only  as 
co-operative  factors,  and  by  no  stretch  of  logic  as 
substitutes. 


Turning  now  to  Mr.  Wallace's  work  on  Darivinism, 
we  have  to  notice,  in  the  first  place,  that  its  doctrine 
differs  from  "  Darwinism  "  in  regard  to  the  important 
dogma  which  it  is  the  leading  purpose  of  that  work 
to  sustain — namely,  that  "the  law  of  utility"  is,  to  all 
intents  and  purposes,  universal,  with  the  result  that 
natural  selection  is  virtually  the  only  cause  of  organic 


Introduction. 


ai 


evolution.  I  say  "to  all  intents  and  purposes."  or 
"virtually,"  because  Mr.  Wallace  does  not  expressly 
maintain  the  ab.stract  impossibility  of  laws  and 
causes  other  than  those  of  utility  and  natural  selec- 
tion ;  indeed,  at  the  <  nd  of  his  treatise,  he  quotes 
with  approval  Darwin's  judf^ainent.  that  "  natural 
selection  has  been  the  most  important,  but  not  the 
exclusive  means  of  modification."  Nevertheless,  as  he 
nowhere  recognizes  any  other  law  or  cause  of  adaptive 
evolution  ^  he  practically  concludes  that,  on  induc- 
tive or  empirical  grounds,  there  is  no  such  other  law 
or  cause  to  be  entertained  — until  we  come  to  the  par- 
ticular case  of  the  human  mind.  But  even  in  making 
this  one  [)articular  exception — or  in  rei)resenting  that 
some  other  law  than  that  of  utility,  and  some  other 
cause  than  that  of  natural  selection,  must  have  been 
concerned  in  evolving  the  mind  of  man — he  is  not 
approximating  his  system  to  that  of  Darwin.  On  the 
contrary,  he  is  but  increasing  the  divergence,  for,  of 
course,  it  was  Darwin's  view  thai  no  such  exception 
could  be  legitimately  drawn  with  respect  to  this 
particular  instance.  And  if,  as  I  understand  must 
be  the  case,  his  expressed  agreement  with  Darwin 
touching  natural  selection  not  being  the  only  cause 
of  adaptive  evolution  has  reference  to  this  point,  the 
quotation  is  singularly  inapt. 

Looking,  then,  to  these  serious  differences  between 
his  own  doctrine  of  evolution — botli  organic  and 
mental — and   that  of  Darwin,    I    cannot   think   that 


'  "The  law  of  correlation,"  and  the  "laws  of  growth,"  he  does 
recognize ;  and  shows  that  they  furnish  an  explanation  of  the  origin 
of  many  characters,  which  cannot  be  brought  under  "  the  law  of 
utility." 


22  Darwin,  and  after  Darwin. 

Mr.  Wallace  has  chosen  a  suitable  title  for  his  book  ; 
because,  in  view  of  the  points  just  mentioned,  it  is 
unquestionable  that  Darwinism  differs  more  widely 
from  the  Origin  of  Species  than  does  the  Origin  of 
Species  from  the  writings  of  the  Neo-Lamarckians. 
But,  passing  over  this  merely  nominal  matter,  a  few 
words  ought  to  be  added  on  the  very  material 
question  regarding  the  human  mind.  In  subsequent 
chapters  the  more  general  question,  or  that  which 
relates  to  the  range  of  utility  and  natural  selection 
elsewhere,  will  be  fully  considered. 
Mr.  Wallace  says, — 

"  The  immense  interest  that  attaches  to  the  origin  of  the 
human  race,  and  the  amount  of  misconception  which  prevails 
regarding  the  essential  teachings  of  Darwin's  theory  on  the 
question,  as  well  as  regarding  my  own  special  views  upon  it, 
induce  me  to  devote  a  final  chapter  to  its  discussion.'* 

Now  I  am  not  aware  that  there  is  any  miscon- 
ception in  any  quarter  as  to  the  essential  teach- 
ings of  Darwin's  theory  on  this  question.  Surely 
it  is  rather  the  case  that  there  is  a  very  general  and 
very  complete  understanding  on  this  point,  both  by 
the  friends  and  the  foes  of  Darwin's  theory — so  much 
so,  indeed,  that  it  is  about  the  only  point  of  similar 
import  in  all  Darwin's  writings  of  which  this  can 
be  said,  Mr.  Wallace's  *'  special  views "  on  the 
other  hand  are,  briefly  stated,  that  certain  features, 
both  of  the  morphology  and  the  psychology  of  man, 
are  inexplicable  by  natural  selection — or  indeed  by 
any  other  cause  of  the  kind  ordinarily  understood 
by  the  term  natural :  they  can  be  explained  only 
by  supposing  "  the  intervention  of  some  distinct 
individual    intelligence,"   which,   however,   need    not 


Introduction. 


23 


necessarily  be  "  one  Supreme  Intelligence,"  but  some 
other  order  of  Personality  standing  anywhere  in 
"  an  infinite  chasm  between  man  and  the  Great  Mind 
of  the  universe^."  Let  us  consider  separately  the 
corporeal  and  the  mental  peculiarities  which  are  given 
as  justifying  this  important  conclusion. 

The  bodily  peculiarities  are  the  feet,  the  hands,  the 
brain,  the  voice,  and  the  naked  skin. 

As  regards  the  feet  Mr.  Wallace  writes,  "  It  is 
difficult  to  see  why  the  prehensile  power  [of  the  great 
toe]  should  have  been  taken  away,"  because,  although 
"  it  may  not  be  compatible  with  perfectly  easy  erect 
locomotion,"  "  how  can  we  conceive  that  early  man, 
as  an  animal^  gained  anything  by  purely  erect 
locomotion  ^  ?  "  But  surely  it  is  not  difficult  to  con- 
ceive this.  In  the  proportion  that  our  simian 
progenitors  ceased  to  be  arboreal  in  their  habits  (and 
there  may  well  have  been  very  good  utilitarian  reasons 
for  such  a  change  of  habitat,  analogous  to  those 
which  are  known  to  have  occurred  in  the  phylogenesis 
of  countless  other  animals),  it  would  clearly  have  been 
of  advantage  to  them  that  their  already  semi-erect 
attitude  should  have  been  rendered  more  and  more 
erect.  To  name  one  among  several  probabilities,  the 
more  erect  the  attitude,  and  the  more  habitually  it  was 
assumed,  the  more  would  the  hands  have  been 
liberated  for  all  the  important  purposes  of  mani- 
pulation. The  principle  of  the  physiological  division 
of  labour  would  thus  have  come  more  and  more  into 
play  :  natural  selection  would  therefore  have  rendered 
the  upper  extremities  more  and  more  suited  to  the 

'  Natural  Selection  and  Iropical  Natun,^,  305;  1 891. 
'  Ibid,  pp.  197-8. 


r  1 


m 


24         Darwin^  and  after  Darwin, 


execution  of  these  purposes,  while  at  the  same  time 
it  would  have  more  and  more  adapted  the  lower  ones 
to  discharging  the  sole  function  of  locomotion.  For 
my  own  part,  I  cannot  perceive  any  difficulty  about 
this :  in  fact,  there  is  an  admirable  repetition  of  the 
process  in  the  ontogeny  of  our  own  children  *, 

Next,  with  regard  to  the  hand,  Mr.  Wallace  says, 
that  it  "  contains  latent  capacities  which  are  unused 
by  savages,  and  must  have  been  even  less  used  by 
palaeolithic  man  and  his  still  ruder  predecessors." 
Thus,  "  it  has  all  the  appearance  of  an  organ  prepared 
for  the  use  of  civilized  man  ^^  Even  if  this  be  true, 
however,  it  would  surely  be  a  dangerous  argument 
to  rely  upon,  seeing  that  we  cannot  say  of  how  much 
importance  it  may  have  been  for  early  man — or  even 
apes — to  have  had  their  power  of  manipulation  pro- 
gressively improved.  But  is  the  statement  true  ?  It 
appears  to  me  that  if  Mr.  Wallace  had  endeavoured 
to  imitate  the  manufactures  that  were  practised  by 
"  palaeolithic  man,"  he  would  have  found  the  very 
best  of  reasons  for  cancelling  his  statement.  For  it 
is  an  extremely  difficult  thing  to  chip  a  flint  into  the 
form  of  an  arrow-head:  when  made,  the  suitable 
attachment  of  it  to  a  previously  prepared  arrow  is  no 
easy  matter :  neither  a  bow  nor  a  bow-string  could 
have  been  constructed  by  hands  of  much  less  per- 
fection than  our  own :  and  the  slaying  of  game  with 
the  whole  apparatus,  when  it  has  been  constructed, 
requires  a  manual  dexterity  which  we  may  be  per- 


*  For  an  excellent  discussion  on  the  ontogeny  of  the  child  in  this 
connexion,  see  Some  Laws  of  Heredity,  by  Mr.  S.  S.  Buckman,  pp.  ago, 
et  seq.  (Proc.  Cotteswold  Nat.  Field  Club,  vol.  z.  p.  3,  189a). 

^  loc.  cit.  p.  198. 


Introduction. 


25 


>> 


fectly  certain  that  Mr.  Wallace — unless  he  has 
practised  the  art  from  boyhood— does  not  possess. 

So  it  is  with  his  similar  argument  that  the  human 
voice  is  more  "  powerful,"  more  "  flexible/'  and  pre- 
sents a  greater  "  range  "  and  "  sweetness  "  than  the 
needs  of  savage  life  can  be  held  to  require.  The  futility 
of  this  argument  is  self-evident  as  regards  "  power." 
And  although  its  weakness  is  not  so  obvious  with 
respect  to  the  other  three  qualities  which  are  named, 
need  we  go  further  than  the  closely  analogous  case  of 
certain  birds  to  show  the  precariousness  of  arguing 
from  such  facts  of  organic  nature  to  the  special 
operation  of  "  a  superior  intelligence  "  ?  I  can  hardly 
suppose  that  Mr.  Wallace  will  invoke  any  such 
agency  for  the  purpose  of  explaining  the  "  latent 
capacities  "  of  the  voice  of  a  parrot.  Yet,  in  many  re- 
spects, these  are  even  more  wonderful  than  those 
of  the  human  voice,  albeit  in  a  wild  state  they  are 
"  never  required  or  used  ^" 

Once  more^  with  regard  to  the  naked  skin,  it  seems 
sufficient  to  quote  the  following  passage  from  the  first 
edition  of  the  Descent  of  Man. 

"The  Rev.  T.  R.  Stebbing,  in  commenting  on  this  view, 
remarks,  that  had  Mr.  Wallace  '  employed  his  usual  ingenuity 
on  the  question  of  man's  hairless  skin,  he  might  have  seen 
the  possibility  of  its  selection  through  its  superior  beauty, 
or  the  health  attaching  to  superior  cleanliness.  At  any  rate 
it  is  surprising  that  he  should  picture  to  himself  a  superior 


m 


'  For  a  discussioa  of  this  remarkable  case,  see  Mental  Evolution  in 
Animals,  pp.  332-3.  It  appears  to  me  that  if  Mr.  Wallace's  argument 
from  the  "latent  capacities  of  the  voice  of  Man"  is  good  for  anything, 
a  fortiori  it  must  be  taken  to  prove  that,  in  the  case  of  the  Parrot,  "  the 
organ  has  been  prepared  in  anticipation  "  of  the  amusement  which  the 
cnltivation  of  its  latent  capacities  arouses  in  "civilized  man." 


26  Darwin^  and  after  Darwin, 


i 


intelligence  plucking  the  hair  from  the  backs  of  savage  men 
(to  whom,  according  to  his  own  account,  it  would  have  been  use- 
ful and  beneficial),  in  order  that  the  descendants  of  the  poor 
shorn  wretches  might,  after  many  deaths  from  cold  and  damp 
in  the  course  of  many  generations,'  have  been  forced  to  raise 
themselves  in  the  scale  of  civiliLdtion  through  the  practice  of 
various  arts,  in  the  manner  indicated  by  Mr.  Wallace  '." 

To  this  it  may  be  added  that  the  Chimpanzee 
"  Sally  "  was  largely  denuded  of  hair,  especially  on 
the  back,  or  the  part  of  "  man's  organization  "  on 
which  Mr.  Wallace  lays  special  stress,  as  being  in  this 
respect  out  of  analogy  with  other  mammalia  ^. 

Lastly,  touching  his  statement  that  the  brain  of 
savage  man  is  both  quantitatively  and  qualitatively 
in  advance  of  his  requirements,  it  is  here  also  sufficient 
to  refer  to  Darwin's  answer,  as  given  in  the  Descent  of 
Man.  Mr.  Wallace,  indeed,  ignores  this  answer  in  his 
recent  re-publication  of  the  argument ;  but  it  is  im- 
possible to  understand  why  he  should  have  done  so. 
To  me,  at  all  events,  it  seems  that  one  out  of  several 
considerations  which  Darwin  advances  is  alone 
sufficient  to  show  the  futility  of  this  argument. 
I  allude  to  the  consideration  that  the  power  of 
forming  abstract  ideas  with  the  complex  machinery 
of  language  as  the  vehicle  of  their  expression,  is 
probably  of  itself  enough  to  account  for  both  the 
mass  and  the  structure  of  a  savage's  brain.  But  this 
leads  us  to  the  second  division  of  Mr.  Wallace's  areu- 

*  Descent  of  Man,  i  st  Ed.  ch.  xx.  (Trans.  Dev,  Assoc,  for  Science,  1 890). 

•  The  late  Prof.  Moseley  informed  me  that,  during  his  voyage  op  the 
Challenger,  he  had  seen  many  men  whose  backs  were  well  covered  with 
hair. — For  an  excellent  discussion  of  the  whole  question,  chiefly  in  the 
light  of  embryology,  see  the  paper  by  Buckman  already  alluded  to, 
pp.  280-289.  Also,  for  an  account  of  an  extraordinary  hairy  race  of  men, 
see  Alone  with  the  Hairy  Ainu,  by  A.  H.  Savage  Landor,  1893. 


•■ft 


4 

M 


:'M 


Introduction. 


27 


M 

i 


ment,  or  that  derived  from  the  mental  endowments 
of  mankind. 

Here  the  pecuh'arities  called  into  evidence  are,  "  the 
Mathematical  Faculty,"  "  the  Artistic  Faculties,"  and 
"the  Moral  Sense."  With  regard  to  the  latter,  he 
avows  himself  a  member  of  the  intuitional  school  of 
ethics ;  but  does  not  prove  a  very  powerful  advocate 
as  again'-t  the  utilitarian  ^. 

It  comts,  then,  to  this.    According  to  Mr.  Wallace's 


*  E.  g.  "  The  special  faculties  we  have  been  ulsctissing  clearly  point  to 
the  existence  in  man  of  something  which  he  has  not  derived  from 
his  animal  progenitors — something  which  we  may  best  refer  to  as 
being  of  a  spiritual  essence  or  nature,  capable  of  progressive  de- 
velopment under  favourable  conditions.  On  the  hypothesis  of  this 
spiritual  nature,  superadded  to  the  animal  nature  of  man,  we  are  able 
to  understand  much  that  is  otherwise  mysterious  or  unintelligible  in 
regard  to  him,  especially  the  enormous  influence  of  ideas,  principles, 
and  beliefs  over  his  whole  life  and  action.  Thus  alone  can  we  understand 
the  constancy  of  the  martyr,  the  unselfishness  of  the  philanthropist, 
the  devotion  of  the  patriot,  the  enthusiasm  of  the  artist,  and  the  resolute 
and  persevering  search  of  the  scientific  worker  after  nature's  secrets. 
Thus  we  may  perceive  that  the  love  of  truth,  the  delight  iii  beauty, 
the  passion  for  justice,  and  the  thrill  of  exultation  with  which  we 
hear  of  any  act  of  courageous  self-sacrifice,  are  ihc  vrorkings  within 
us  of  a  higher  nature  which  has  not  been  developed  by  means  of  the 
struggle  for  material  existence."  {Darwinism,  p.  474.)  I  have  quoted 
this  whole  paragraph,  because  it  is  so  inconsistent  with  the  rest  of 
Mr.  Wallace's  system  that  a  mere  epitome  of  it  might  well  have  been 
suspected  of  error.  Given  an  intellectual  being,  howsoever  produced, 
and  what  is  there  "mysterious  or  unintelligible"  in  "the  enormous 
influence  of  ideas,  principles,  and  beliefs  over  his  whole  life  and 
action"?  Or  again,  if  he  be  also  a  social  being,  what  is  the  relevancy 
of  adducing  •'  tlie  constancy  of  the  martyr,"  "  the  unselfishness  of  the 
philanthropist,"  "the  devotion  of  the  patriot,"  "the  love  of  truth," 
"the  passion  for  justice,"  "the  thrill  of  exultation  when  we  hear  of  any 
act  of  courageous  self-sacrifice,"  in  evidence  against  the  law  of  utility , 
or  in  order  to  prove  that  a  "  nature "  thus  endowed  has  "  not  been 
developed  by  means  of  the  struggle  for  existence,"  when  once  this 
struggle  has  been  transferred  from  individuals  to  communities  ?  The 
whole  passage  reads  like  an  ironical  satire  in  favour  of  "  Darwinism," 
rather  than  a  serious  argument  against  it. 


I.i 


ft] 

til 


28  Darwin^  and  after  Darwin. 

eventual  conclusion,  man  is  to  be  separated  from  the 
rest  of  organic  nature,  and  the  stcaay  progress  of 
evolution  by  natural  causes  is  to  be  regarded  as 
stopped  at  its  final  stage,  because  the  human  mind 
presents  the  laculties  of  mathematical  calculation  and 
aesthetic  perception.  Surely,  on  antecedent  grounds 
alone,  it  must  be  apparent  that  there  is  here  no  kind 
of  proportion  between  the  conclusion  and  the  data  from 
which  it  is  drawn.  That  we  are  not  confined  to 
any  such  grounds,  I  will  now  try  to  show. 

Let  it  be  remembered,  however,  that  in  the  following 
brief  criticism  I  am  not  concerned  with  the  issue  as 
to  whether,  or  how  far,  the  "  faculties "  in  question 
have  owed  their  origin  or  their  development  to 
natural  selection.  I  am  concerned  only  with  the 
doctrine  that  in  order  to  account  for  s'lch  and  such 
particular  "  faculty  "  of  the  human  mind,  some  order 
of  causation  must  be  supposed  other  than  what  we 
call  natural.  I  am  not  a  Neo- Darwinist,  and  so 
have  no  desire  to  make  "  natural  selection  "  synonym- 
ous with  '* natural  causation"  throughout  the  whole 
domain  of  life  and  of  mind.  And  I  quite  agree 
with  Mr.  Wallace  that,  at  any  rate,  the  "aesthetic 
faculty  "  cannot  conceivably  have  been  produced  by 
natural  selection — seeing  that  it  is  of  no  conceivable 
life-serving  value  in  any  of  the  stages  of  its  growth. 
Moreover,  it  appears  to  me  that  the  same  thing  has  to 
be  said  of  the  play  instincts,  sense  of  the  ludicrous,  and 
sundry  other  "  faculties "  of  mind  among  the  lower 
animals.  It  being  thus  understood  that  I  am  not 
differing  from  Mr.  Wallace  where  he  imposes  "limits" 
on  the  powers  of  natural  .selection,  but  only  where  he 
seems  to  take  for  granted  that  this  is  the  same  thing 


Introduction. 


29 


as  imposing  limits  on  the  powers  of  natural  causation, 
my  criticism  is  as  follows. 

In  the  first  place,  it  is  a  psychological  fallacy  to 
regard  the  so-called  "  faculties  "  of  mind  as  analogous 
to  "  organs  "  of  the  body.  To  classify  the  latter  with 
reference  to  the  functions  which  they  severally  perform 
is  to  follow  a  natural  method  of  classification.  But 
it  is  an  artificial  method  which  seeks  to  partition 
mental  faculty  into  this,  that,  and  the  other  mental 
faculties.  Like  all  other  purely  artificial  classifications, 
this  one  has  its  practical  uses ;  but,  also  like 
them,  it  is  destitute  of  philosophical  meaning.  This 
statement  is  so  .well  recognized  by  psychologists,  that 
there  is  no  occasion  to  justify  it.  But  I  must  remark 
that  any  cogency  which  Mr.  Wallace's  argument  may 
appear  to  present,  arises  from  his  not  having  recognized 
the  fact  which  the  statement  conveys.  For,  had  he 
considered  the  mind  as  a  whole,  instead  of  having 
contemplated  it  under  the  artificial  categories  of 
constituent  "  faculties,"  he  would  probably  not  have 
laid  any  such  special  stress  upon  some  of  the  latter. 
In  other  words,  he  would  have  seen  that  the  general 
development  of  the  human  mind  as  a  whole  has 
presumably  involved  the  growth  of  those  conven- 
tionally abstracted  parts,  which  he  regards  as  really 
.separate  endowments.  Or,  if  he  should  fird  it  easier 
to  retam  the  terms  of  his  metaphor,  we  may  answer 
him  by  saying  that  the  ''  faculties "  of  mind  are 
"correlated,"  like  "organs"  of  the  body;  and,  there- 
fore, that  any  general  development  of  the  various 
other  "faculties"  have  presumably  entailed  a  collateral 
development  of  the  two  in  question. 

Again,  in  the  second  place,  \x  would  seem   that 


30  Darwin,  and  after  Darwin. 


Mr.  Wallace  has  not  sufficiently  considered  the  co- 
operation of  other  well-known  natural  causes,  which 
must  have  materially  assisted  the  survival  of  the 
fittest  where  these  two  "  faculties "  are  concerned. 
For,  even  if  we  disregard  the  inherited  effects  of 
use — which,  however,  if  entertained  as  possible  in  any 
degree  at  alL  must  have  here  constituted  an  important 
factor, — there  remain  on  the  one  hand,  the  un- 
questionable Influences  of  individual  education  arj, 
on  the  other  hand,  of  the  selection  principle  operating 
in  the  mind  itself. 

Taking  these  two  points  separately,  it  is  surely 
sufficiently  well  known  that  individual  education — 
or  special  training,  whether  of  mind  or  body — usually 
raises  congenital  powers  of  any  kind  to  a  more 
or  less  considerable  level  above  those  of  the  normal 
type.  In  other  \  'ords,  whatever  doubt  there  may  be 
touching  the  mherited  effects  of  use,  there  can  be  no 
question  touching  the  immense  developmental  effects 
thereof  in  the  individual  life-time.  Now,  the  conditions 
of  savage  life  are  not  such  as  lead  to  any  deliberate 
cultivation  of  the  "faculties"  either  of  the  mathematical 
or  aesthetic  order.  Consequently,  as  might  be  ex- 
pected, we  find  both  of  them  in  what  Mr.  Wallace 
regards  as  but  a  "  latent "  stage  of  development.  But 
in  just  the  same  way  do  we  find  that  the  marvellous 
powers  of  an  acrobat  when  specially  trained  from  child- 
hood— say  to  curve  his  spine  backwards  until  his  teeth 
can  bite  his  heels — are  "  latent "  in  all  men.  Or,  more 
correctly,  they  are  potential  in  every  child.  So  it  is 
with  the  prodigious  muscular  development  of  a  trained 
athlete,  and  with  any  number  of  other  cases  where 
either  the  body  or  the  mind  is  concerned.     Why  then 


.;fl' 


■S 


Si 

i 


m 


Introduction. 


31 


■'\-T- 


should  Mr.  Wallace  select  the  particular  instances  of 
the  mathematical  and  aesthetic  powers  in  savages  as  in 
any  special  sense  '*  prophetic  "  of  future  development 
in  trained  members  of  civilized  races  ?  Although  it 
is  true  that  these  "latent  capacities  and  powers  are 
unused  by  savages,"  is  it  not  equally  true  that  savages 
fail  to  use  their  latent  capacities  and  powers  as 
tumblers  and  athletes?  Moreover,  is  it  not  likewise 
true  that  as  used  by  sa^'  es,  or  as  occurring  normally 
in  man,  such  capacities  and  powers  arc  no  less  poorly 
developed  than  are  those  of  the  "  faculties  "  on  which 
Mr.  Wallace  lays  so  much  stress?  In  other  words, 
are  not  "latent  capacities  and  powers"  of  all  kinds 
more  or  less  equally  in  excess  of  anything  that  is  ever 
required  of  them  by  man  in  a  state  of  nature  ?  There- 
fore, if  we  say  that  where  mathematics  and  the  fine 
arts  are  concerned  the  potential  capacities  of  savage 
man  are  in  some  mystical  sense  "  prophetic "  of 
a  Newton  or  a  Beethoven,  so  in  consistency  ought  we 
to  say  that  in  these  same  capacities  we  discern  a 
similar  prophecy  of  thivie  other  uses  of  civilized  life 
which  we  have  in  a  rope-dancer  or  a  clown. 

Again,  and  in  addition  to  this,  it  should  be  remem- 
bered that,  even  if  we  do  suppose  any  prophecy  of 
this  kind  where  the  particular  capacities  in  question 
are  concerned,  we  must  clearly  extend  the  reference  to 
the  lower  animals.  Not  a  few  birds  display  aesthetic 
feelings  in  a  measure  fairly  comparable  with  those  of 
savages;  while  we  know  that  some  animals  present 
the  germs  of  a  "  faculty  "  of  computation  ^     But.  it  is 

'  See  Proc.  Zool.  Soc.  June  4,  1 889,  for  an  account  of  the  performances 
in  this  respect  of  the  Chimpanzee  "  Sally."  Also,  for  some  remarks  on 
the  psychology  of  the  subject,  in  Mental  Evolution  in  Man,  p.  215, 
I  should  like  to  take  this  opportunity  of  stating  that,  after  the  two 


f  i 


32  Darwin f  and  after  Darwin, 

needless  to  add,  this  fact  is  fatal  to  Mr.  Wallace's 
argument  as  I  understand  it — viz.  that  the  "  faculties  " 
in  question  have  been  in  some  special  manner  com- 
municated by  some  superior  intelligence  to  man. 

Once  more,  it  is  obviously  unfair  to  select  such  men  as 
a  *'  Newton,  a  La  Place,  a  Gauss,  or  a  Cayley  "  for  the 
purpose  of  estimating  the  difference  between  savages 
and  civilized  man  in  regard  to  the  latter  "faculty.' 
These  men  are  the  picked  mathematicians  of  centuries. 
Therefore  they  are  men  who  not  only  enjoyed  all 
the  highest  possible  benefits  of  individual  culture,  but 
likewise  those  who  have  been  most  endowed  with 
mathematical  power  congenitally.  So  to  speak,  they 
are  the  best  variations  in  this  particular  direction 
which  our  race  is  known  to  have  produced.  But 
had  such  variations  arisen  among  savages  it  is 
sufficiently  obvious  that  they  could  have  come  to 
nothing.  Therefore,  it  is  the  normal  average  of 
"  mathematical  faculty  "  in  civilized  man  that  should 
be  contrasted  with  that  of  savage  man ;  and,  when 
due  regard  is  paid  to  the  all-important  consideration 
which  immediately  follows,  I  cannot  feel  that  the 
contrast  presents  any  difficulty  to  the  theory  of  human 
evolution  by  natural  causation. 

Lastly,  the  consideration  just  alluded  to  is,  that 
civilized  man  enjoys  an  advantage  over  savage  man 
far  in  advance  even  of  those  which  arise  from  a  set- 
tled state  of  society,  incentives  to  intellectual  training, 
and  so  on.  This  inestimable  advantage  consists  in 
the  art  of  writing,  and  the  consequent   transmission 

publications  above  referred  to,  this  animal's  instruction  was  continued, 
and  that,  before  her  death,  her  ''counting"  extended  as  far  as  ten. 
That  is  to  say,  any  number  of  straws  asked  for  from  one  to  ten  would 
always  be  correctly  given. 


Introduction. 


33 


of  the  effects  of  culture  from  generation  to  generation. 
Quite  apart  from  any  question  as  to  the  hereditary 
transmission  of  acquired  characters,  we  have  in  this 
intellectual  transmission  of  acquired  experience  a 
means  of  accumulative  cultivation  quite  beyond  our 
powers  to  estimate.  For.  unlike  all  other  cases  where 
wc  recognize  the  great  influence  of  individual  use  or 
practice  in  augmenting  coni^^enital  ''faculties"  (such 
as  in  the  athlete,  pianist,  &c.),  in  this  case  the  effects  of 
special  cultivation  do  not  end  with  the  individual  life, 
but  are  carried  on  and  on  through  successive  genera- 
tions ad  infinitum.  Hence,  a  civilized  man  inherits 
mentally,  if  not  physically,  the  effects  of  culture  for 
ages  past,  and  this  in  whatever  direction  he  may  choose 
to  profit  therefrom.  Moreover — and  I  deem  this 
an  immensely  important  addition — in  this  unique 
department  of  purely  intellectual  transmission,  a 
kind  of  non-physical  natural  selection  is  perpetually 
engaged  in  producing  the  best  results.  For  here 
a  struggle  for  existence  is  constantly  taking  place 
among  "  ideas,"  "  methods,"  and  so  forth,  in  what 
may  be  termed  a  psychological  environment.  The 
less  fit  are  superseded  by  the  more  fit,  and  this  not 
only  in  the  mind  of  the  individual,  but,  through  lan- 
guage and  literature,  still  more  in  the  mind  of  the  race. 
"A  Newton,  a  La  Place,  a  Gauss,  or  a  Cayley," 
would  all  alike  have  been  impossible,  but  for  a  pre- 
viously prolonged  course  of  mental  evolution  di^ie  to  the 
selection  principle  operating  in  the  region  of  mathe- 
matics, by  means  of  continuous  survivals  of  the  best 
products  in  successive  generations.  And,  of  course, 
the  same  remark  applies  to  art  in  all  its  branches  *. 

'  In  Prof.  Lloyd  Morgan's  Animal  Life  and  Intelligence  there  is  an 
II.  D 


I  I 


I- J 


I 


34  Darwin^  and  after  Darwin. 


Quitting  then  the  last,  and  in  my  opinion  the 
weakest  chapter  of  Danvinism,  the  most  important 
points  presented  by  other  portions  of  this  work  are — 
to  quote  its  author's  own  enumeration  of  them — an 
attempted  "  proof  that  ail  specific  characters  are  (or 
once  have  been)  either  useful  in  themselves  or  corre- 
lated with  useful  characters":  an  attempted  "proof 
that  natural  selection  can,  in  certain  cases,  increase 
the  sterility  of  crosses  ":  an  attempted  *'  proof  that 
the  effects  of  use  and  disuse,  even  if  inherited,  must  be 
overpowered  by  natural  selection " :  an  attempted 
proof  that  the  facts  of  variation  in  nature  are  in  them- 
selves sufficient  to  meet  the  diflficulty  which  arises 
against  the  theory  of  natural  selection,  as  held  by  him, 
from  the  swamping  effects  of  free  inter-crossing :  and, 
lastly,  "  a  fuller  discussion  on  the  colour  relations  of 
animals,  with  additional  facts  and  arguments  on  the 
origin  of  sexual  differences  of  colour."  As  I  intend  to 
deal  with  all  these  points  hereafter,  excepting  the  last, 
it  will  be  suflficient  in  this  opening  chapter  to  remark, 
that  in  as  far  as  I  disagree  with  Mr.  Wallace  (and 
agree  with  Darwin\  on  the  subject  of  "sexual 
differences  of  colo^*,  ^ny  reasons  for  doing  so  have 
been  already  sufficiently  stated  in  Part  I.  But  there 
is  much  else  in  his  treatment  of  this  subject  which 
appears  to  me  highly  valuable,  and  therefore  present- 
ing an  admirable  contribution  to  the  literature  of 
Darwinism.  In  particular,  it  appears  to  me  that  the 
most    important   of    his    views    in    this    connexion 

admirable  discussion  on  this  subject,  which  has  been  published  since  the 
above  was  written.  The  same  has  to  be  said  of  Weismann's  Essay  on 
Music,  where  much  that  I  have  here  said  is  anticipated.  With  the  views 
and  arguments  which  Mr.  Mivart  has  forcibly  set  forth  I  have  already 
dealt  to  the  best  of  my  ability  in  a  work  on  Mental  Evolution  in  Man. 


Introduction. 


35 


probably  represents  the  truth — namely,  that,  among 
the  higher  animals,  more  or  less  cons[)icuous  pecu- 
liarities of  colour  have  often  been  acquired  for  the 
purpose  of  enabling  members  of  the  same  species 
quickly  and  certainly  to  recognize  one  another. 
This  theory  was  first  published  by  Mr.  J.  E.  Todd, 
in  18H8,  and  therefore  but  a  short  time  before  its 
re-publication  by  Mr.  Wallace.  As  his  part  in  the 
matter  has  not  been  sufficiently  recognized,  I  should 
like  to  conclude  this  introductory  chapter  by  drawing 
prominent  attention  to  the  merits  of  Mr.  Todd's 
paper.  For  not  only  has  it  the  merit  of  priority,  but 
it  deals  with  the  whole  subject  of  *'  recognition 
colours" — or,  as  he  calls  them,  "directive  colours" — 
in  a  more  comprehensive  manner  than  has  been  done 
by  any  of  his  successors.  In  particular,  he  shovvrs 
that  the  principle  of  recognition-marking  is  not  re- 
stricted to  facilitating  sexual  intercourse,  but  extends 
also  to  several  other  matters  of  importance  in  the 
economy  of  animal  life  ^. 

Having  thus  briefly  sketched  the  doctrines  of  the 
sundry  Post-Darwinian  Schools  from  a  general  point 
of  view,  I  shall  endeavour  throughout  the  rest  of  this 
treatise  to  discuss  in  appropriate  detail  the  questions 
which  have  more  specially  come  to  the  front  in  the 
post-Darwinian  period.  It  can  scarcely  be  said  that 
any  one  of  these  questions  has  arisen  altogether  de 
novo  during  this  period  ;  for  glimmerings,  more  or 
less  conspicuous,  of  all  are  to  be  met  with  in  the 
writings  of  Darwin  himself.  Nevertheless  it  is  no 
less  true  that  only  after  his  death  have  they  been 

'  American  Naturalist,  xxii.  pp.  201-207. 

D    2 


f 


i 


X 


* 


36  Darwin,  and  after  Darwin. 


It        ';i 


I  I 


lighted  up  to  the  full  blaze  of  active  discussion  *.  By 
far  the  most  important  of  them  are  those  to  which 
the  rest  of  this  treatise  will  be  confined.  They  are 
four  in  number,  ^nd  it  is  noteworthy  that  they  are  all 
intimately  connected  with  the  great  question  which 
Darwin  spent  the  best  years  of  his  life  in  contem- 
plating, and  which  has  therefore,  in  one  form  or 
another,  occupied  the  whole  of  the  present  chapter — 
the  question  as  to  whether  natural  selection  has  been 
the  sole  cause,  or  but  the  chief  cause  of  modification. 
The  four  questions  above  alluded  to  appertain 
respectively  to  Heredity,  Utility,  Isolation,  and  Physio- 
logical Selection.  Of  these  the  first  two  will  form 
the  subject-matter  of  the  present  volume,  while  the 
last  two  will  be  dealt  with  in  the  final  instalment  of 
Darwin,  and  after  Darwin 

'  It  is  almost  needless  to  say  that  besides  the  works  mentioned  in  this 
chapter,  many  others  have  been  added  to  the  literature  of  Darwinism 
since  Darwin's  death.  But  as  none  of  these  profess  to  contain  much 
that  is  original,  I  have  not  thought  it  necessary  to  consider  any  of  them 
in  this  merely  general  review  of  the  period  in  question.  In  subsequent 
chapters,  however,  allusions  will  be  made  to  those  among  them  which 
I  deem  of  most  importance. 

[Since  this  note  was  written  and  printed  the  following  works  have 
been  published  to  which  it  does  not  apply :  Animal  Life  and  Intelli- 
gence, by  Professor  Lloyd  Morgan;  The  Colours  of  Animals,  by 
Professor  Poulton ;  and  Materials  for  the  Study  of  Variation,  by 
Mr.  Bateson.  All  these  works  are  of  high  value  and  importance. 
Special  reference  should  also  be  made  to  Professor  Weismann's  Essays.] 


SECTION   I 


HEREDITY 


)  II 


CHAPTER   II. 


Characters  as  Hereditary  and  Acquired 
(Preliminary). 

We  will  proceed  to  consider,  throughout  Section  I 
of  the  present  work,  the  most  important  among  those 
sundry  questions  which  have  come  to  the  front 
since  the  death  of  Darwin.  For  it  was  in  the  year 
after  this  event  that  Weismann  published  the  first 
of  his  numerous  essays  on  the  subject  of  Heredity, 
and,  unquestionably,  it  has  been  these  essays  which 
have  given  such  prominence  to  this  subject  during 
the  last  decade. 

At  the  outset  it  is  desirable  to  be  clear  upon 
certain  points  touching  the  history  of  the  subject; 
the  limits  within  which  our  discussion  is  to  be  con- 
fined ;  the  relation  in  which  the  present  essay  stands 
to  the  one  that  I  published  last  year  under  the 
title  An  Examination  of  Weismannism  \  and  several 
other  matters  of  a  preliminary  kind. 

The  problems  presented  by  the  phenomena  of 
heredity  are  manifold ;  but  chief  among  them  is 
the  hitherto  unanswered  question  as  to  the  trans- 
nr.ission  or  non-transmission  of  acquired  characters. 
This  is  the  question  to  which  the  present  Section 
will  be  confined. 

Although  it  is  usually  supposed  that  this  question 


i 

\ 

\ 

1 

t' 


P'i 


m 


40  Darwm,  and  after  Darwin, 

was  first  raised  by  Weismann,  such  was  not  the  case. 
Any  attentive  reader  of  the  successive  editions  of 
Darwin's  works  may  perceive  that  at  least  from  the 
year  1859  he  had  the  question  clearly  before  his 
mind ;  and  that  during  the  rest  of  his  life  his 
opinion  with  regard  to  it  underwent  considerable 
modifications — becoming  more  and  more  Lamarckian 
the  longer  that  he  pondered  it.  Bu*  it  was  not  till 
1875  that  the  question  was  clearly  presented  to 
the  general  public  by  the  independent  thought  of 
Mr.  Galton,  who  was  led  to  challenge  the  Lamarckian 
factors  in  toto  by  way  of  deduction  from  his 
theory  of  Stirp — the  close  resemblance  of  which  to 
Professor  Weismann's  theory  of  Germ-plasm  has 
been  shown  in  my  Examination  of  Weismannism. 
Lastly,  I  was  myself  led  to  doubt  the  Lamarck- 
ian factors  still  further  back  in  the  seventies, 
by  having  found  a  reason  for  questioning  the  main 
evidence  which  Mr.  Darwin  had  adduced  in  their 
favour.  This  doubt  was  greatly  strengthened  on 
reading,  in  the  following  year,  Mr.  Galton's  Theory 
of  Heredity  just  alluded  to ;  and  thereupon  I  com- 
menced a  prolonged  course  of  experiments  upon  the 
subject,  the  general  nature  of  which  will  be  stated 
in  future  chapters.  Presumably  many  other  persons 
must  have  entertained  similar  misgivings  touching  the 
inheritance  of  acquired  characters  long  before  the 
publication  of  Weismann's  first  essay  upon  the  subject 
in  1883.  The  question  as  to  the  inheritance  of 
acquired  characters  was  therefore  certainly  not  first 
raised  by  Weismann — although,  of  course,  there  is 
no  doubt  that  it  was  conceived  by  him  independently, 
and  that  he  had  the  great  merit  of  calling  general 


Characters,  Hereditary  and  Acquired,  41 

attention  to  its  existence  and  importance.  On  the 
other  hand,  it  cannot  be  said  that  he  has  succeeded  in 
doing  very  much  towards  its  solution.  It  is  for  these 
reasons  that  any  attempt  at  dealing  with  Weismann's 
fundamental  postulate — i.e.  that  of  the  non-inherit- 
ance of  acquired  characters — was  excluded  from  my 
Examination  of  Weismannism.  As  there  stated  he  is 
justified  in  assuming,  for  the  purposes  of  his  discussion, 
a  negative  answer  to  the  question  of  such  inheritance ; 
but  evidently  the  question  itself  ought  not  to  be  in- 
cluded within  what  we  may  properly  understand  by 
"  Weismannism."  Weismannism,  properly  so  called, 
is  an  elaborate  system  of  theories  based  on  the  funda- 
mental postulate  just  mentioned — theories  having 
reference  to  the  mechanism  of  heredity  on  the  one  hand, 
and  to  the  course  of  organic  evolution  on  the  other. 
Now  it  was  the  object  of  the  foregoing  Examination  to 
deal  with  this  system  of  theories  per  se ;  and  therefore 
we  have  here  to  take  a  new  point  of  departure  and 
to  consider  separately  the  question  of  fact  as  to  the 
inheritance  or  non-inheritance  of  acquired  characters. 
At  first  sight,  no  doubt,  it  will  appear  that  in  adopting 
this  method  I  am  putting  the  cart  before  the  horse. 
For  it  may  well  appear  that  I  ought  first  to  have 
dealt  with  the  validity  of  Weismann's  postulate,  and 
not  till  then  to  have  considered  the  system  of  theories 
which  he  has  raised  upon  it.  But  this  criticism  is 
not  likely  to  be  urged  by  any  one  who  is  well  ac- 
quainted with  the  questions  at  issue.  For,  in  the  first 
place,  it  is  notorious  that  the  question  of  fact  is 
still  open  to  question ;  and  therefore  it  ought  to  be 
considered  separately,  or  apart  from  any  theories 
which  may  have  been  formed  with  regard  to  it.     In 


\ 

\ 

\ 

\ 


4a 


Darwin^  and  after  Darwin. 


im 


!i|l 


»1  111! 


1 


II  I 


the  second  place,  our  judgement  upon  this  question 
of  fact  must  be  largely  influenced  by  the  validity  of 
general  reasonings,  such  as  those  put  forward  in  the 
interests  of  rival  theories  of  heredity ;  and,  as  the 
theory  of  germ-plasm  has  been  so  thoughtfully 
elaborated  by  Professor  Weismann,  I  have  sought  to 
give  it  the  attention  which  it  deserves  as  preliminary 
to  our  discussion  of  the  question  of  fact  which  now  lies 
before  us.  Thirdly  and  lastly,  even  if  this  question 
could  be  definitely  answered  by  proving  either  that 
acquired  characters  are  inherited  or  that  they  are  not, 
it  would  by  no  means  follow  that  Weismann's  theory 
of  heredity  would  be  proved  wholly  false  in  the  one 
case,  or  wholly  true  in  the  other.  That  it  need  not 
be  wholly  true,  even  were  its  fundamental  postulate  to 
be  proved  so,  is  evident,  because,  although  the  fact 
might  be  taken  to  prove  the  theory  of  Continuity,  the 
theory  of  Germ-plasm  is,  as  above  stated,  very  much 
more  than  this.  That  the  theory  of  Germ-plasm 
need  not  be  wholly  false,  even  if  acquired  characters 
should  ever  be  proved  heritable,  a  little  thought  may 
easily  show,  because,  in  this  event,  the  further  question 
would  immediately  arise  as  to  the  degrees  and  the 
comparative  frequency  of  such  inheritance.  For  my 
own  part,  as  stated  in  the  Examination,  I  have  always 
been  disposed  to  accept  Mr.  Galton's  theory  of  Stirp 
in  preference  to  that  of  Germ-plasm  on  this  very 
ground — i.  e.  that  it  does  not  dogmatically  exclude  the 
possibility  of  an  occasional  inheritance  of  acquired 
characters  in  faint  though  cumulative  degrees.  And 
whatever  our  individual  opinions  may  be  touching  the 
admissi  jility  of  such  a  via  media  between  the  theories 
of  Pangenesis  and  Germ-plasm,  at  least  we  may  all 


Characters^  Hereditary  and  Acquired.   43 


agree  on  the  desirability  of  fully  considering  the 
matter  as  a  ^preliminary  to  the  discussion  of  the 
question  of  fact. 

As  it  is  not  to  be  expected  that  even  those  who 
may  have  read  my  previous  essaj^  can  now  carry  all 
these  points  in  their  memories  I  will  here  re-state 
them  in  a  somewhat  fuller  form. 

The  following  diagram  will  serve  to  give  a  clearer 
view  of  the  sundry  parts  of  Professor  Weismann's 
system  of  theories,  as  well  as  of  their  relations  to  one 
another. 


\ 


\ 


\ 


\ 


•f  4'- 


/ 


/ 


.? 


^ 

/ 

V 

M 

£ 

A 

^ 

S 

JS 

^ 

« 

Q. 

^ 

i 

« 

u 

0 

M 

« 

*« 

0 

s 

>» 

§ 

•3 

'€ 

.3 

s 

a 

8 

^ 

Postulate  as  to  the  absolute  non-inheritance  of  acquired  characters. 

Now,  as  just  explained,  the  parts  of  this  system 
which  may  be  properly  and  distinctively  called 
'■  Weismannism  "  are  those  which  go  to  form  the 
Y-like  structure  of  deductions  from  the  fundamental 
postulate.     Therefore,  it  was  the   Y-like  system  of 


\ 

V 


44  Darwtfif  and  after  Darwin. 


■  % 

i  m 

"I 

"I 


deductions  which  were  dealt  with  in  the  Examination 
of  Weismannism,  while  it  is  only  his  basal  postulate 
which  has  to  be  dealt  with  in  the  following  chapters. 

So  much,  then,  for  the  relations  of  Weismann's 
system  of  theories  to  one  another.  It  is,  however,  of 
even  more  importance  that  we  should  gain  a  clear 
view  of  the  relations  between  his  theory  of  heredity 
to  those  of  Darwin  and  of  Galton,  as  preliminary  to 
considering  the  fundamental  question  of  fact. 

As  we  have  already  seen,  the  theory  of  germ-plasm 
is  not  only  a  theory  of  heredity :  it  is  also,  and  more 
distinctively,  a  theory  of  evolution,  &c.  As  a  theory 
of  heredity  it  is  grounded  on  its  author's  fundamental 
postulate — the  continuity  of  germ -plasm.  But  as  a 
theory  of  evolution,  it  requires  for  its  support  this 
additional  postulate,  that  the  continuity  of  germ- 
plasm  has  been  absolute  "since  the  first  origin  of 
life."  It  is  clear  that  this  additional  postulate  is  not 
needed  for  his  theory  of  heredity,  but  only  for  his 
additional  theory  of  evolution,  &c.  There  have  been 
one  or  two  other  theories  of  heredity,  prior  to  this  one, 
which,  like  it.  have  been  founded  on  the  postulate  of 
Continuity  of  the  substance  of  heredity  ;  but  it  has 
not  been  needful  for  any  of  these  theories  to  postulate 
further  that  this  substance  has  been  always  thus 
isolated,  or  even  that  it  is  now  invariably  so.  For 
even  though  the  isolation  be  frequently  invaded  by 
influences  of  body-changes  on  the  congenital  characters 
of  this  substance,  it  does  not  follow  that  this  principle 
of  Continuity  may  not  still  be  true  in  the  main,  even 
although  it  is  supplemented  in  some  degree  by  that 
of  use-inheritance.  Indeed,  so  far  as  the  pheno- 
mena of  heredity  are  concerned,  it  is  conceivable  that 


Characters f  Hereditary  and  Acquired.  45 


all  congenital  characters  were  originally  acquired, 
and  afterwards  became  congenital  on  account  of  their 
long  inheritance.  I  do  not  myself  advocate  this  view 
as  biologically  probable,  but  merely  state  it  as  logically 
possible,  and  in  order  to  show  that,  so  far  as  the 
phenomena  of  heredity  are  concerned,  there  appears 
to  be  no  reason  for  Weismann's  deduction  that  the 
principle  of  Continuity,  if  true  at  all.  must  be  absolute. 
And  it  would  further  appear  the  only  reason  why  he 
makes  this  deduction  (stem  of  the  Y)  is  in  order  to 
provide  a  foundation  for  his  further  theories  of  evolu- 
tion, &c.  (arms  of  the  Y).  It  is  indeed  necessary  fo. 
these  further  theories  that  body-changes  should 
never  exercise  any  hereditary  influence  on  the  heredi- 
tary endowments  of  germ-plasm,  and  therefore  it  is 
that  he  posits  the  substance  of  heredity  as,  not  only 
continuous,  but  uninterruptably  so  "since  the  first 
origin  of  life." 

Now,  this  may  be  made  more  clear  by  briefly  com- 
paring Weismann's  theory  with  those  of  Darwin  and 
of  Galton.  Weismann's  theory  of  heredity,  then, 
agrees  with  its  predecessors  which  we  are  considering 
in  all  the  following  respects.  The  substance  of  heredity 
is  particulate ;  is  mainly  lodged  in  highly  specialized 
cells  ;  is  nevertheless  also  distributed  thoughout  the 
general  cellular  tissues,  where  it  is  concerned  in  all 
processes  of  regeneration,  repair,  and  a-sexual  repro- 
duction ;  presents  an  enormously  complex  structure, 
iii  that  every  constituent  part  of  a  potentially  future 
organism  is  represented  in  a  fertilized  ovum  by  cor- 
responding particles;  is  everywhere  capable  of  virtually 
unlimited  multiplication,  without  ever  losing  its  here- 
ditary endowments ;    is  often   capable  of   carrying 


I'll 

I 

\ 

si 

I 


Il 

Ml 


46  Dm^n,  and  after  Darwin, 

these  endowments  in  a  dormant  state  through  a  long 
series  of  generations  until  at  last  they  re-appear 
in  what  we  recognize  as  recursions.  Thus  far  all 
three  theories  are  in  agreement.  In  fact,  the  only- 
matter  of  an/  great  importance  wherein  th-^y  disagree 
has  reference  to  the  doctrine  of  Continuity^.  For 
while  Darwin's  theory  supposes  the  substance  of 
heredity  to  be  mainly  formed  anew  in  each  ontogeny, 
and  therefore  that  the  continuity  of  this  substance  is 
for  the  most  part  interrupted  in  every  generation  ^, 
Waismann's  theory  supposes  this  substance  to  be 
formed  only  during  the  phylogeny  of  each  species, 
and  therefore  to  have  been  absolutely  uninterrupted 
since  the  first  origin  of  life. 

But  now,  Galton's  theory  of  heredity  stands  much 
nearer  to  Weismann's  in  this  matter  of  Continuity ; 
for  it  is,  as  he  says,  a  theory  of  '  modified  pangenesis," 
and  the  modification  consists  in  allowing  very  much 
more  for  the  principle  of  Continuity  than  is  lowed 
by  Darwin's  theory  ;  in  fact  he  expresses  himself  as 
quite  willing  to  adopt  (on  adequate  grounds  being 
shown)  the  doctrine  of  Continuity  as  absolute,  and 
therefore  propounded,  as  logically  possible,  the  iden- 
tical theory  which  was  afterwards  and  independently 
announced  by  Weismann.  Or,  to  quote  his  own 
words — 

"  We  might  almost  reserve  our  belief  that  the  structural  [i.  e. 
somatic]  cells  ran  react  on  the  sexual  elements  at  all,  and  we 

'  Originally,  Weismann's  further  assumption  as  to  the  perpetual 
stability  of  germ-plasm,  "  since  the  first  origin  of  sexual  reproduction," 
was  another  very  important  point  of  difference,  but  this  has  now  been 
withdrawn. 

*  1  say  "  mainly  formed  anew,"  and  "for  the  most  part  interrupted," 
Lccause  even  Darwin's  theory  does  not,  as  is  generally  supposed,  exclude 
the  doctrine  of  Continuity  in  toto. 


Characters,  Hereditary  and  Acquired.   47 


may  be  confident  that  at  most  they  do  so  in  a  very  faint  degree: 
in  other  words,  '.hat  acquired  modifications  are  barely,  if  at  all, 
inherited,  in  the  correct  sense  of  that  word '." 

So  far  Mr.  Galton  ;  but  for  Weismann's  further 
theory  of  evolution,  &c.,  it  is  necessary  to  postulate 
the  additional  doctrine  in  question  ;  and  it  makes 
a  literally  inimeasurable  difference  to  any  theory  of 
evolution  whether  or  not  we  entertain  this  additional 
postulate.  For  no  matter  how  faintly  or  how  fitfully 
the  substance  of  heredity  may  be  modified  by  somatic 
tissues,  the  Lamarckian  principles  are  hypothetically 
allowed  some  degree  of  pl^y.  And  although  this  is 
a  lower  degree  than  Darwin  supposed,  their  infiuence 
in  determining  the  course  of  organic,  evolution  may 
still  have  been  enormous  ;  seeing  that  their  action  in 
any  degree  must  always  have  been  directive  of  varia- 
tion on  the  one  hand,  and  cumulative  on  the  other. 

Thus,  by  merely  laying  this  theory  side  by  side 
with  Weismann's,  we  can  perceive  at  a  glance  how 
a  pure  theory  of  heredity  admits  of  being  based 
on  the  postulate  of  Continuity  alone,  without  cum- 
bering itself  by  any  further  postulate  as  to  this 
Continuity  being  absolute.  And  this,  in  my  opinion 
is  the  truly  scientific  attitude  of  mind  for  us  to  adopt 
as  preliminary  to  the  following  investigation.  For 
the  whole  investigation  will  be  concerned — and  con- 
cerned only — with  this  question  of  Continuity  as  ab- 
solute, or  as  admitting  of  degrees.  There  is,  without 
any  question,  abundant  evidence  to  prove  that  the 
substance  of  heredity  is  at  least  partly  continuous 
(Gemmules).  It  may  be  that  there  is  also  abundant 
evidence  to  prove  this  substance  much  more  largely 

'  Theory  of  Hefdity  (Juurn.  Anlhrop.  List.  1875,  p.  346). 


s 


48 


DarwiUf  and  after  Darwin. 


,-:  MS 


n 


•Ml; 


continuous  than  Darwin  supposed  (Stirp) ;  but  be  this 
as  it  may,  it  is  certain  that  any  such  question  as  to 
the  degree  of  continuity  differs,  toto  each,  from  that  as 
to  whether  there  can  ever  be  any  continuity  at  all. 

How,  then,  we  may  well  ask,  is  it  that  so  able 
a  naturalist  and  so  clear  a  thinker  as  Weismann 
can  have  so  far  departed  from  the  inductive  methods 
as  to  have  not  merely  propounded  the  question 
touching  Continuity  and  its  degrees,  or  even  of  Con- 
tinuity as  absolute  ;  but  to  have  straightway  assumed 
the  latter  possibility  as  a  basis  on  which  to  run 
a  system  of  branching  and  ever-changing  speculations 
concerning  evolution,  variation,  the  ultimate  struc- 
ture of  living  material,  the  intimate  mechanism  of 
heredity,  or,  in  short,  such  a  system  of  deductive 
conjectures  as  has  never  been  approached  in  the 
history  of  science?  The  answer  to  this  question  is 
surely  not  far  to  seek.  Must  it  not  be  the  answer 
already  given?  Must  it  not  have  been  for  the  sake 
of  rearing  this  enormous  structure  of  speculation 
that  Weismann  has  adopted  the  assumption  of 
Continuity  as  absolute?  As  we  have  just  seen, 
Galton  had  well  shown  how  a  theory  of  heredity 
could  be  founded  on  the  general  doctrine  of  Con- 
tinuity, without  anywhere  departing  from  the  in- 
ductive methods — even  while  fully  recognizing  the 
possibility  of  such  continuity  as  absolute.  But 
Galton's  theory  was  a  "  Theory  of  Heredity^*  and 
nothing  more.  Therefore,  while  clearly  perceiving 
that  the  Continuity  in  question  may  be  absolute, 
he  saw  no  reason,  either  in  fact  or  in  theory,  for 
concluding  that  it  mttst  be.  On  the  contrary,  he 
saw  that  this  question  is,  for  the  present,  necctssarily 


Characters^  Hereditary  and  Acquired.    49 


unripe  for  profitable  discussion — and,  a  fortiori,  for 
the  shedding  of  clouds  of  seed  in  all  the  directions 
of "  Wcismaniiism." 

Hence,  what  I  desire  to  be  borne  in  mind  through- 
out the  following  discussion  is,  that  it  will  have 
exclusive  reference  to  the  question  of  fact  already 
stated,  without  regard  to  any  superjacent  theories  ; 
and,  still  more,  that  there  is  a  vast  distinction 
between  any  question  touchin;^  the  degrees  in  which 
acquired  characters  are  transmitted  to  progeny,  and 
the  question  as  to  whether  they  are  ever  trans- 
mitted in  any  degree  at  all.  Now,  the  latter  question, 
being  of  much  greater  importance  than  the  former, 
is  the  one  which  will  mainly  occupy  our  attention 
throughout  the  rest  of  this  Section. 

We  have  already  seen  that  before  the  subject  was 
taken  up  by  Weismann  the  difference  between  acquired 
and  congenital  characters  in  respect  to  transmissibility 
was  generally  taken  to  be  one  of  degree  ;  not  one  of 
kind.  It  was  usually  supposed  that  acquired  chi." 
acters,  although  not  so  fully  and  not  so  certainly 
inherited  as  congenital  characters,  nevertheless  were 
inherited  in  some  lesser  degree  ;  so  that  if  the  same 
acquired  character  continued  to  be  successively  ac- 
quired in  a  number  of  sequent  generations,  what  was 
at  first  only  a  slight  tendency  to  be  inherited  would 
become  by  summation  a  more  aad  more  pronounced 
tendency,  till  eventually  the  acquired  character  might 
become  as  strongly  inherited  as  a  congenital  one. 
Or,  more  precisely,  it  was  supposed  that  an  acquired 
character,  in  virtue  of  such  a  summation  of  hereditary 
influence,  would  in  time  become  congenital.  Now, 
if  this  supposition  be  true,  it  is  evident  that  more  or 

II.  £ 


I  • 


'i 


•X 

y 


i-sll 


50  Darwin,  and  after  Darwin. 


lit 


I'!  *'■ 
I, 


less  assistance  must  be  lent  to  natural  selection  in 
its  work  of  evolving  adaptive  modifications  ^  And 
inasmuch  as  we  know  to  what  a  wonderful  extent 
adaptive  modifications  are  secured  during  individual 
life-times — by  the  direct  action  of  the  environment  on 
the  one  hand,  and  by  increased  or  diminished  use  of 
special  organs  and  mental  faculties  on  the  other — it 
becomes  obvious  of  what  importance  even  a  small 
measure  of  transmissibility  on  their  part  would  be 
in  furnishing  to  natural  selection  ready-made  varia- 
tions in  required  directions,  as  distinguished  from 
promiscuous  variations  in  all  directions.  Contrari- 
wise, if  functionally-produced  adaptations  and  adapta- 
tions produced  by  the  direct  action  of  the  environ- 
ment are  never  transmitted  in  any  degree,  not  only 


m 

Ml 


*  Mr.  Piatt  Ball  has,  indeed,  argued  that  "  use-inheritance  would  often 
be  an  evil,"  since,  for  example,  "the  condyle  of  the  human  jaw  would 
become  larger  than  the  body  of  the  jaw,  liecause  as  the  fulcruiri  of  the 
lever  it  receives  more  pressure";  and  similarly  as  regards  many  other 
hypothetical  cases  which  he  mentions.  ( The  Effects  of  Use  and  Disuse, 
pp.  128-9  ^^  ^'9-)  ^^^  i^  ^s  evident  that  this  argument  proves  too  much. 
For  if  the  effects  of  use  and  disuse  as  transmitted  to  progeny  would  be 
an  evil,  it  could  only  be  because  these  effects  as  they  occur  in  the  parents 
are  an  evil — and  this  they  most  certainly  are  not,  being,  on  the  contrary 
and  as  a  general  rule,  of  a  high  order  of  adaptive  value.  Moreover,  in  the 
race,  there  is  a  superadded  agency  always  at  work,  which  must  effect- 
ually prevent  any  undue  accumulation  of  these  effects — namely,  natural 
selection,  which  every  Darwinist  accepts  as  a  controlling  principle  of  all 
or  any  other  principles  of  change.  Therefore,  if,  as  first  produced  in 
the  life-time  of  individuals,  the  effects  of  use  and  disuse  are  not  injurious, 
much  less  can  they  become  so  if  transmitted  through  the  life-time  of 
species.  Again,  Mr.  Wallace  argues  that,  even  supposing  use-inheritance 
to  occur,  its  adapting  work  in  the  individual  can  never  extend  to  the 
race,  seeing  that  the  natural  selection  of  fortuitous  variations  in  the 
directions  required  must  always  produce  the  adaptations  more  quickly 
than  would  be  possible  by  use-inheritance.  This  argument,  being  one 
of  more  weight,  will  be  dealt  with  in  a  future  chapter. 


Characters,  Hereditary  and  Acquired.   51 


would  there  be  an  incalculable  waste,  so  to  speak,  of 
adaptive  modifications — these  being  all  laboriously 
and  often  most  delicately  built  up  during  life-times  of 
individuals  only  to  i">e  thrown  down  again  as  regards 
the  interest  of  species — but  so  large  an  additional 
burden  would  be  thrown  upon  the  shoulders  of  natural 
selection  that  it  becomes  difficult  to  conceive  how 
even  this  gigantic  principle  could  sustain  it,  as  I  shall 
endeavour  to  show  more  fully  in  future  chapters.  On 
the  other  hand,  however,  Weismann  and  his  followers 
not  only  feel  no  difficulty  in  throwing  overboard  all 
this  ready-made  machinery  for  turning  out  adaptive 
modifications  when  and  as  required ;  but  they  even 
represent  that  by  so  doing  they  are  following  the 
logical  maxim,  Entia  non  sunt  multiplicanda  praeter 
necessitatem — which  means,  in  its  relation  to  causality, 
that  we  must  not  needlessly  multiply  hypothetical 
principles  to  explain  given  results.  But  when  appeal 
is  here  made  to  this  logical  principle — the  so-called 
Law  of  Parsimony — two  things  are  forgotten. 

In  the  first  place,  it  is  forgotten  that  the  very 
question  in  debate  is  whether  causes  of  the  Lamarck- 
ian  order  are  unnecessary  to  explain  all  the  phe- 
nomena of  organic  nature.  Of  course  if  it  could  be 
proved  that  the  theory  of  natural  selection  alone 
is  competent  to  explain  all  these  phenomena,  appeal 
to  the  logical  principle  in  question  would  be  justi- 
fiable. But  this  is  precisely  the  point  which  the 
followers  of  Darwin  refuse  to  accept ;  and  so  long  as 
it  remains  the  very  point  at  issue,  it  is  a  mere  begging 
the  question  to  represent  that  a  class  of  causes  which 
have  hitherto  been  regarded  as  necessary  are,  in 
fact,  unnecessary.     Or,,  in  other  words,  when  Darwin 

E  2 


•5 


5a 


Darwin^  and  after  Darwin. 


11  ^ ; 


N 


ti 

m 
ill 


himself  so  decidedly  held  that  these  causes  are  neces- 
sary as  supplements  to  natural  selection,  the  burden 
of  proof  is  quite  as  much  on  the  side  of  VVeismann 
and  his  followers  to  show  that  Darwin's  opinion 
was  wrong,  as  it  is  on  the  side  of  Darwin's  followers 
to  show  that  it  was  right.  Yet,  notwithstanding  the 
elaborate  structure  of  theory  which  Weismann  has 
raised,  there  is  nowhere  one  single  fact  or  one  single 
consideration  of  much  importance  to  the  question 
in  debate  which  was  not  perfectly  well  known  to 
Darwin.  Therefore  I  say  that  all  this  challenging 
of  Darwinists  to  justify  their  "  Lamarckian  assump- 
tions" really  amounts  to  nothing  more  than  a  pitting 
of  opinion  against  opinion,  where  there  is  at  least  as 
much  call  for  justification  on  the  one  side  as  on  the 
other. 

Again,  when  these  challenges  are  thrown  down  by 
Weismann  and  his  followers,  it  appears  to  be  forgotten 
that  the  conditions  of  their  own  theory  are  such  as 
to  render  acceptance  of  the  gauge  a  matter  of  great 
difficulty.  The  case  is  very  much  like  that  of  a 
doughty  knight  pitching  his  glove  into  the  sea,  and 
then  defying  any  antagonist  to  take  it  up.  That  this 
is  the  case  a  very  little  explanation  will  suffice  to 
show. 

The  question  to  be  settled  is  whether  acquired 
characters  are  ever  transmitted  by  heredity.  Now 
suppose,  for  the  sake  of  argument,  that  acquired 
characters  are  transmitted  by  heredity — though  not  so 
fully  and  not  so  certainly  as  congenital  characters — 
how  is  this  fact  to  be  proved  to  the  satisfaction  of 
Weismann  and  his  followers?  First  of  all  they 
answer, — Assuredly  by  adducing  experimental  proof 


Characters^  Hereditary  and  Acquired.   53 


of  the  inheritance  of  injuries,  or  mutilations.  But 
in  making  this  answer  they  appear  to  forget  that 
Darwin  has  already  shown  its  inefficiency.  That  the 
self-styled  Neo-Lamarckians  have  been  much  more 
unguarded  in  this  respect.  I  fully  admit ;  but  it  is 
obviously  unfair  to  identify  Darwin's  views  with  those 
of  a  small  section  of  evolutionists,  who  are  really  as 
much  opposed  to  Darwin's  teaching  on  one  side  as  is 
the  school  of  Weismann  on  the  other.  Yet,  on  read- 
ing the  essays  of  Weismann  himself — and  still  more 
those  of  his  followers— one  would  almost  be  led  to 
gather  that  it  is  claimed  by  him  to  have  enunciated 
the  dir  Unction  between  congenital  and  acquired  char- 
acters in  respect  of  transmissibility ;  and  therefore 
also  to  have  first  raised  the  objection  which  lies 
against  the  theory  of  Pangenesis  in  respect  of  the 
non-transmissibility  of  mutilations.  In  point  of  fact, 
however,  Darwin  is  as  clear  and  decided  on  these 
points  as  Weismann.  And  his  answer  to  the  obvious 
difficulty  touching  the  non-transmissibility  of  mutila- 
tions is,  to  quote  his  own  words,  '*  the  long-continued 
inheritance  of  a  part  which  has  been  removed  during 
many  generations  is  no  real  anomaly,  for  gem  mules 
formerly  derived  from  the  part  are  multiplied  and 
transmitted  from  generation  to  generation  \"  There- 
fore, so  far  as  Darwin's  theory  is  concerned,  the 
challenge  to  produce  evidence  of  the  transmission  of 
injuries  is  irrelevant :  it  is  no  more  a  part  of  Darwin's 
theory  than  it  is  of  Weismann's  to  maintain  that 
injuries  are  transmitted. 

There  is,  however,  one  point  in  this  connexion  to 
which  allusion  must  here  be  made.     Although  Darwin 

'   Variation  under  Domestication,  ii.  393. 


\ 

\ 

h 

1 


54  Darwin y  and  after  Darwin. 


■  i\ 
»), 
•I 

« 


tl  I 


did  not  believe  in  the  transmissibility  of  mutilations 
when  these  consist  merely  in  the  amputation  of  parts 
of  an  organism,  he  did  believe  in  a  probable  tendency 
to  transmission  when  removal  of  the  part  is  followed 
by  gangrene.  For,  as  he  says,  in  that  case  all  the 
gemmules  of  the  mutilated  or  amputated  part,  as  they 
are  gradually  attracted  to  that  part  (in  accordance 
with  the  law  of  affinity  which  the  theory  assumes), 
will  be  successively  destroyed  by  the  morbid  process. 
Now  it  is  of  importance  to  note  that  Darwin  made 
this  exception  to  the  general  rule  of  the  non-trans- 
missibility  of  mutilations,  not  because  his  theory  of 
pangenesis  required  it,  but  because  there  appeared  to 
be  certain  very  definite  observations  and  experiments 
— which  v/ill  be  mentioned  later  on — proving  that 
when  mutilations  are  followed  by  gangrene  they  are 
apt  to  be  inherited :  his  object,  therefore,  was  to 
reconcile  these  alleged  facts  with  his  theory,  quite  as 
much  as  to  sustain  his  theory  by  such  facts. 

So  much,  then,  for  the  challenge  to  produce 
direct  evidence  of  the  transmissibility  of  acquired 
characters,  so  far  as  mutilations  are  concerned : 
believers  in  Darwin  s  theory,  as  distinguished  from 
Weismann's,  are  under  no  obligation  to  take  up  such 
a  challenge.  But  the  challenge  does  not  end  here. 
Show  us,  say  the  school  of  Weismann,  a  single  in- 
stance where  an  acquired  character  of  any  kind  (be  it 
a  mutilation  or  otherwise)  has  been  inherited :  this  is 
all  that  we  require :  this  is  all  that  we  wait  for :  and 
surely,  unless  it  be  acknowledged  that  the  Lamarckian 
doctrine  reposes  on  mere  assumption,  at  least  one 
such  case  ought  to  be  forthcoming.  Well,  nothing 
can  sound  more  reasonable  than  this  in  the  first  in- 


Characters f  Hereditary  and  Acquired.  55 

stance  ;  but  as  soon  as  we  begin  to  cast  about  for 
cases  which  will  satisfy  the  Neo-Darwinians,  we  find 
that  the  structure  of  their  theory  is  such  as  to  pre- 
clude, in  almost  every  conceivable  instance,  the  possi- 
bility of  meeting  their  demand.  For  their  theory  begins 
by  assuming  that  natural  selection  is  the  one  and  only 
cause  of  organic  evolution.  Consequently,  what  their 
demand  amounts  to  is  throwing  upon  the  other  side 
the  burden  of  disproving  this  assumption — or,  in  other 
words,  of  proving  thi,  negative  that  in  any  given  case  of 
transmitted  adaptation  natural  selection  has  not  been 
the  sole  agent  at  work.  Now,  it  must  obviously  be 
in  almost  all  cases  impossible  to  prove  this  negative 
among  species  in  a  state  of  nature.  For,  even  sup- 
posing that  among  such  species  Lamarckian  prin- 
ciples have  had  a  large  share  in  the  formation  of 
hereditary  and  adaptive  characters,  how  would  Weis- 
mann  himself  propose  that  we  should  set  about  the 
proof  of  such  a  fact,  where  the  proof  demanded  by  his 
assumption  is,  that  the  abstract  possibility  of  natural 
selection  having  had  anything  to  do  with  the  matter 
must  be  excluded?  Obviously  this  is  impossible  in 
the  case  of  inherited  characters  which  are  also 
adaptive  characters.  How  then  does  '"•  fare  with  the 
case  of  inherited  characters  which  are  not  also 
adaptive?  Merely  that  this  case  is  met  by  another 
and  sequent  assumption,  which  constitutes  an  integral 
part  of  the  Neo-Darwinian  creed — namely,  that  in 
nature  there  can  be  no  stick  characters.  Seeing  that 
natural  selection  is  taken  to  be  the  only  possible 
cause  of  change  in  species,  it  follows  that  all  changes 
occurring  in  species  must  necessarily  be  adaptive, 
whether  or  not  we  are  able  to  perceive  the  adaptations. 


m 


IF 

i 

•5:" 

•5: 

I'' 

•53 

1^1 


sfi 


DanvtHf  and  after  Darwin, 


\n 


'  'If 


I 


:i 


:)« 


In  this  way  apparently  useless  characters,  as  well  as 
obviously  useful  ones,  are  ruled  out  of  the  question : 
that  is  to  say,  all  hereditary  characters  of  species  in 
a  state  of  nature  are  assumed  to  be  due  to  natural 
selection,  and  then  it  is  demanded  that  the  validity  of 
this  assumption  should  be  disproved  by  anybody  who 
doubts  it.  Yet  Weismann  himself  would  be  unable 
to  suggest  any  conceivable  method  by  which  it  can 
be  disproved  among  species  in  a  state  of  nature — and 
this  even  supposing  that  the  assumption  is  entirely 
false  ^ 

Consequently,  the  only  way  in  which  these 
speciously-sounding  challenges  can  be  adequately  met 
is  by  removing  some  individuals  of  a  species  from 
a  state  of  nature,  and  so  from  all  known  influences 
of  natural  selection  ;  then,  while  carefully  avoiding 
artificial  selection,  causing  these  individuals  and  their 
progeny  through  many  generations  unduly  to  exer- 
cise some  parts  of  their  bodies,  or  unduly  to  fail  in 
the  exercise  of  others.  But,  clearly,  such  an  experi- 
ment is  one  that  must  take  years  to  perform,  and 
therefore  it  is  now  too  early  in  the  day  to  reproach 
the  followers  of  Darwin  with  not  having  met  the 
challenges  which  are  thrown  down  by  the  followers 
of  Weismann^. 

'  In  subsequent  chapters,  especially  devoted  to  the  question  (i.e. 
Section  II),  the  validity  of  this  assumption  will  be  considered  on 
its  own  merits. 

■  I  say  "  the  followers  of  Weismann,"  because  Weismann  himself,  with 
bis  clear  perception  of  the  requircmentsof  experimental  research,  expressly 
states  the  above  considerations,  with  the  conclusions  to  which  they 
lead.  Nevertheless,  he  is  not  consistent  in  his  utterances  upon  this 
matter ;  for  he  frequently  expresses  himself  to  the  effect,  "  that  the  onus 
probandi  rests  with  my  opponents,  and  therefore  they  ought  to  bring 
forward  actual  proofs  "  {Essays,  i.  p.  390).     But,  as  above  shown,  the 


Characters,  Hereditary  and  Acquired.    57 

Probably  enough  has  now  been  said  to  show  that 
the  Neo-Darwinian  assumption  precludes  the  possi- 
bih'ty  of  its  own  disproof  from  any  of  the  facts  of 
nature  (as  distinguished  from  domestication)— and 
this  even  supposing  that  the  assumption  be  false.  On 
the  other  hand,  of  course,  it  equally  precludes  the 
possibility  of  its  own  proof;  and  therefore  it  is  as 
idle  in  Darwinists  to  challenge  Weismann  for  proof  of 
his  negative  (i.e.  that  acquired  characters  are  not  trans- 
mitted), as  it  is  in  Weismann  to  challenge  Darwinists 
for  proof  of  the  opposite  negative  (i.  e.  that  all 
seeming  cases  of  such  transmission  are  not  due  to 
natural  selection).  This  dead-lock  arises  from  the 
fact  that  in  nature  it  is  beyond  the  power  of  the 
followers  of  Darwin  to  exclude  the  abstract  possi- 
bility of  natural  selection  in  any  given  case,  while  it  is 
equally  beyond  the  power  of  the  followers  of  Weismann 
to  exclude  the  abstract  possibility  of  T  amarckian 
principles.  Therefore  at  present  the  question  must 
remain  for  the  most  part  a  matter  of  opinion,  based 
upon  general  reasoning  as  distinguished  from  special 
facts  or  crucial  experiments.  The  evidence  available 
on  either  side  is  presumptive,  not  demonstrative  ^ 
But  it  is  to  be  hoped  that  in  the  future,  when  time 
shall  have  been  allowed  for  the  performance  of  definite 
experiments  on  a  number  of  generations  of  domesti- 
cated plants  or  animals,  intentionally  shielded  from 
the  influences  of  natural  selection  while  exposed  to 
those  of  the  L?j.marckian   principles,  results  will   be 

onus  rests  as  much  with  him  as  with    his  o|>poiiL;its ;   while,  even  if 
his  opponents  are  light,    he  elsewhere  recognizes  that  they  can  bring 
"actual   iiroofs"   of  the   fact  only  as  a  result  of  experiments  which 
must  take  many  years  to  perform. 
»  Note  A. 


i 


58 


Darwin,  and  after  Darwin. 


•1 

4 


* 
■♦if 


i|| 


grained  which  will  finally   settle   the   question   one 
way  or  the  other. 

Meanwhile,  however,  we  must  be  content  with  the 
evidence  as  it  stands  ;  and  this  will  lead  us  to  the 
second  division  of  our  subject.  That  is  to  say,  having 
r-^w  dei  It  with  the  antecedent,  or  merely  logical, 
St  lie  Kfi  the  question,  we  have  next  to  consider  what 
actr^^  V  biological,  evidence  there  is  at  present 
avaiuole  c  ''ither  side  of  it.  Thus  far.  neither  side 
in  the  debate  has  any  advantage  over  the  other.  On 
grounds  of  general  reasoning  alone  they  both  have 
to  rely  on  more  or  less  dogmatic  assumptions.  For 
it  is  equally  an  unreasoned  statement  of  opinion 
whether  we  allege  that  all  the  phenomena  of  organic 
evolution  can  be,  or  can  not  be,  explained  by  the 
theory  of  natural  selection  alone.  We  are  at  present 
much  too  ignorant  touching  the  causes  of  organic 
evolution  to  indulge  in  dogmatism  of  this  kind ; 
and  if  the  question  is  to  be  referred  for  its  answer 
to  authority,  it  would  appear  that,  both  in  respect 
of  number  and  weight,  opinions  on  the  side  of  having 
provisionally  to  retain  the  Lamarckian  factors  are 
more  authoritative  than  those  per  contra  ^. 

Turning  then  to  the  question  of  fact,  with  which 
the  following  chapters  are  concerned,  I  will  conclude 
this  preliminary  one  with  a  few  words  on  the  method 
of  discussion  to  be  adopted. 

First  I  will  give  the  evidence  in  favour  of  Lamarck- 
ianism ;    this    will   occupy   the    next    two    chapters. 


*  For  a  fair  and  careful  statement  of  the  present  balance  of  authoritative 
opinion  upon  the  question,  see  H.  F.  Osborn,  American  Naturalist ^ 
1892,  pp.  537-67. 


Characters f  Hereditary  and  Acquired.    59 


Then,  in  Chapter  V,  I  will  similarly  give  the  evidence 
per  contra,  or  in  favour  of  Continuity  as  absolute. 
Lastly,  I  will  sum  up  the  evidence  on  both  sides, 
and  give  my  own  judgement  on  the  whole  case.  But 
on  whichever  side  I  am  thus  acting  as  special  pleader 
for  the  time  being,  I  will  adduce  only  such  arguments 
as  seem  to  me  valid — excluding  alike  from  both  the 
many  irrelevant  or  otherwise  invalid  reasonings  which 
have  been  but  too  abundantly  published.  Moreover, 
I  think  it  will  be  convdnient  to  or  't'der  all  that  has 
been  said — or  may  be  said — in  \W  ^  y  of  criticism 
to  each  argument  by  the  opp*"^^^  ^\.q  while  such 
argument  is  under  discussion  -i.  e.  not  to  wait  till 
all  the  special  pleading  on  one  side  shall  have  been 
exhausted  before  considering  )?  exceptions  which 
have  been  (or  admit  of  being)  taken  to  the  arguments 
adduced,  but  to  deal  with  such  exceptions  at  the  time 
when  each  of  these  arguments  shall  have  been  severally 
stated.  Again,  and  lastly,  I  will  arrange  the  evidence 
in  each  case — i.  e.  on  both  sides — under  three 
headings,  viz.  (A)  Indirect,  (B)  Direct,  and  (C)  Ex- 
perimental*. 

'  [The  above  paragraph  is  allowed  to  remain  exactly  as  Mr.  Romanes 
left  it.  Chapteis  V  and  V'l  were  however  not  completed.  >S'm  uute 
appended  to  Preface.    C  LI.  M.] 


?^ 


1:? 


1 


s 


"SI 


1    '*»!, 

<  ^^ 


'1"  . 


CHAPTER  III. 

ClIAUACTKKS   AS   HEREDITARY  AND   ACQUIRED 

(continued). 


IN 


■1  ^ 


(A.) 

Indirect  Evidence  in  favour  of  the  Inheritance 
of  Acquired  Characters. 

Starting  with  the  evidence  in  favour  of  the  so- 
called  Lamarckian  factors,  we  have  to  begin  with  the 
Indirect — and  this  without  any  special  reference  to 
the  theories,  either  of  Weismann  or  of  others. 

It  has  already  been  shown,  while  setting  forth  in 
the  preceding  chapter  the  antecedent  standing  of  the 
issue,  that  in  this  respect  the  prima  facie  presump- 
tion is  wholly  on  the  side  of  the  transmission,  in 
greater  degree  or  less,  of  acquired  characters.  Even 
Weismann  allows  that  all  '•  appearances "  point  in 
this  direction,  while  there  is  no  inductive  evidence 
of  the  action  of  natural  selection  in  any  one  case, 
either  as  regards  germs  or  somas,  and  therefore, 
a  fortiori,  of  the  "all-sufficiency"  of  this  caused  It 
is  true  that  in  some  of  his  earlier  essays  he  has 
argued  that  there  is  no  small  weight  of  prima  facie 
evidence  in  favour  of  his  own  views  as  to  the  non- 

'  See,  especially,  his  excellent  remarks  on  this  point,  Contetfip.  Kev 
Sept.  1893. 


i  <l 


Characters,  Hereditary  and  Actjnired.    6i 

inheritance  of  acquired  characters.  This  however, 
will  have  to  be  considered  in  its  proper  place  further 
on.  Meanwhile  I  shall  say  merely  in  general  terms 
that  it  arises  almost  entirely  from  a  confusion  of 
the  doctrine  of  Continuity  as  absolute  with  that  of 
Continuity  as  partial,  and  therefore  as  admitting  of 
degrees  in  different  cases  -which,  as  already  ex- 
plained, are  doctrines  wide  as  the  poles  asunder. 
But,  leaving  aside  for  the  present  such  prima  facie 
evidence  as  Weismann  has  adduced  on  his  side 
of  the  issue,  I  may  quote  him  as  a  hostile  witness 
to  the  weight  of  this  kind  of  evidence  per  contra^ 
in  so  far  as  it  has  already  been  presented  in  the 
foregoing  chapter.  Indeed,  Weismann  is  much  too 
logical  a  thinker  not  to  perceive  the  cogency  of 
the  "  appearances "  which  lie  against  his  view  of 
Continuity  as  absolute — although  he  has  not  been 
sufficiently  careful  in  distinguishing  between  such 
Continuity  and   that  which  admits  of  degrees. 

We  may  take  it,  then,  as  agreed  on  all  hands  that 
whatever  weight  merely  prima  facie  evidence  may  in 
this  matter  be  entitled  to,  is  on  the  side  of  what 
I  have  termed  moderated  Lamarckianism  :  first  sight 
"  appearances "  are  against  the  Neo-Darwinian  doc- 
trine of  the  absolute  non-inheritance  of  acquired 
characters. 


n 


1  • 


'   i; 


Let    us    now   turn    to    another    and    much    more 


tavour 


of 


important   line   of  indirect    evidence    in 
moderated  Lamarckianism. 

The  difficulty  of  excluding  the  possibility  of  na- 
tural selection  having  been  at  work  in  the  case  of 
wild   plants   and  animals  has  already  been  noticed. 


62  Danvin,  and  after  Darzvtn. 


II' 


'1 

H 

i 


Therefore  we  may  now  appreciate  the  importance 
of  all  facts  or  arguments  wliich  attenuate  the  prob- 
ability of  natural  selection  having  been  at  work. 
This  may  be  done  by  searching  for  cases  in  nature 
where  a  congenital  structure,  although  uncjuestionably 
adaptive,  nevertheless  presents  so  small  an  amount 
of  adaptation,  that  we  can  scarcely  suppose  it  to 
have  been  arrived  at  by  natural  selection  in  the 
struggle  for  existence,  as  distinguished  from  the 
inheritance  of  functionally-produced  modifications. 
For  if  functionally-produced  modifications  are  ever 
transmitted  at  all,  there  is  no  limit  to  the  minute- 
ness of  adaptive  values  which  may  thus  become 
congenital  ;  whereas,  in  order  that  any  adaptive 
structure  or  instinct  should  be  seized  upon  and  ac- 
cumulated by  natural  selection,  it  must  from  the 
very  first  have  had  an  adaptive  value  sufficiently 
great  to  have  constituted  its  presence  a  matter  of 
life  and  death  in  the  struggle  for  existence.  Such 
structures  or  instincts  must  not  only  have  always 
presented  some  measure  of  adaptive  value,  but 
this  must  always  have  been  sufficiently  great  to 
reach  \vhat  I  have  elsewhere  called  a  selection- 
value.  Hence,  if  we  meet  with  cases  in  nature  where 
adaptive  structures  or  instincts  present  so  low  a 
degree  of  adaptive  value  that  it  is  difficult  to  con- 
ceive how  they  could  ever  have  exercised  any 
appreciable  influence  in  the  battle  for  life,  such  cases 
may  fairly  be  adduced  in  favour  of  the  Lamarckian 
theory.  P'or  example,  the  Neo- Lamarckian  school  of 
the  United  States  is  chiefly  composed  of  palaeon- 
tologists ;  and  the  reason  of  this  seems  to  be  that 
the  study  of  fossil  forms — or  of  species  in  process  of 


Characters,  Hereditary  and  Acijiiired.   63 


formation — reveals  so  many  instances  of  adaptations 
which  in  their  nascent  condition  present  such  ex- 
ceedingly minute  degrees  of  adaptive  value,  that  it 
seems  unreasonable  to  attribute  their  development  to 
a  survival  of  tlic  fittest  in  the  complex  strui^gle  for 
existence.  But  as  this  argument  is  in  my  opinion 
of  greatest  force  when  it  is  applied  to  certain  facts 
of  physiology  with  which  I  am  about  to  deal,  I  will 
not  occup>  ipace  by  considering  any  of  the  number- 
less cases  to  which  the  Neo-Lamarckians  apply  it 
within  the  region  of  palaeontology'. 

Turning  then  to  inherited  actions,  it  is  nere  that 
we  might  antecedently  expect  to  find  our  best  evi- 
dence of  the  Lamarckian  principles,  if  these  principles 
have  really  had  any  share  in  the  process  of  adaptive 
evolution.  For  we  know  that  in  the  life-time  of 
individuals  it  is  action,  and  the  cessation  of  action, 
which  produce  nearly  all  the  phenomena  of  acquired 
adaptation —use  and  disuse  in  animals  being  merely 
other  names  for  action  and  the  cessation  of  action. 
Again,  we  know  that  it  is  where  neuro-muscular 
machinery  is  concerned  that  we  meet  with  the  most 
conclusive  evidence  of  the  remarkable  extent  to 
which  action  is  capable  of  co-ordinating  structures 
for  the  ready  performance  of  particular  functions ; 
so  that  even  during  the  years  of  childhood  '•  practice 
makes  perfect "  to  the  extent  of  organizing  neuro- 
muscular adjustments,  so  elaborate  and  complete  as 
to  be  indistinguishable  from  those  which  in  natural 

*  There  is  now  an  extensive  literature  within  this  region.  The  principal 
writers  are  Cope,  Scott  and  Osborn.  Unfortunately,  howev  •»•,  the 
facts  adduced  are  not  crucial  as  test-cases  betw>»en  the  rival  therries — 
nearly  all  of  thtm,  in  fact,  being  equally  suscejtible  of  expkiia'.  on  by 
either. 


I 


I  I 


64 


Darwin,  and  after  Darwin. 


species  we  recognized  as  reflex  actions  on  the  one 
hand,  and  instinctive  actions  on  the  other.  Hence, 
if  there  be  any  such  thing  as  "  use-inheritance  *'  at 
all,  it  is  in  the  domain  of  reflex  actions  and  instinc- 
tive actions  that  we  may  expect  to  find  our  best 
evidence  of  the  fact.  Therefore  I  will  restrict  the 
present  line  of  evidence — (A) — to  these  two  classes 
of  phenomena,  as  together  yielding  the  best  evidence 
obtainable  within  this  line  of  argument. 


II' 


J  1*1 

rvk 
i ... 


M 

*  ti. 


The  evidence  in  favour  of  the  Lamarckian  factors 
which  may  be  derived  from  the  phenomena  of  reflex 
action  has  never,  I  believe,  been  pointed  out  before ; 
but  it  appears  to  me  of  a  more  cogent  nature  than 
perhaps  any  other.  In  order  to  do  it  justice,  I  will 
begin  by  re-stating  an  argument  in  favour  of  these 
factors  which  has  already  been  adduced  by  previous 
writers,  and  discussed  by  myself  in  published  corre- 
spondence with  several  leaders  of  the  ultra-Darwinian 
school. 

Long  ago  Professor  Broca  and  Mr.  Herbert  Spencer 
pointed  to  the  facts  of  co-adaptation,  or  co-ordination 
within  the  limits  of  the  same  organism,  as  presenting 
good  evidence  of  Lamarckian  principles,  working  in 
association  with  natural  selection.  Thus,  taking  one 
of  Lamarck's  own  illustrations,  Mr.  Spencer  argued 
that  there  must  be  numberless  changes — extending  to 
all  the  organs,  and  even  to  all  the  tissues,  of  the 
animal — which  in  the  course  of  many  generations 
have  conspired  to  convert  an  antelope  into  a  giraffe. 
Now  the  point  is,  that  throughout  the  entire  history 
of  these  changtb  their  utility  must  always  have  been 
dependent  on  their  association.     It  would  be  useless 


Characters,  Hereditary  and  Acquired.    65 


that  an  incipient  giraffe  should  present  the  peculiar 
form  of  the  hind-quarters  which  we  now  perceive, 
unless  at  the  same  time  it  presented  the  correspond- 
ingly peculiar  form  of  the  fore-quarters ;  and  as  each 
of  these  great  modifications  entails  innumerable  sub- 
ordinate modifications  throughout  both  halves  of  the 
creature  concerned,  the  chances  must  have  been  in- 
finitely great  against  the  required  association  of  so  many 
changes  happening  to  have  arisen  congenitally  in  the 
same  individuals  by  way  of  merely  fortuitous  variation. 
Yet,  if  we  exclude  the  Lamarckian  interpretation, 
which  gives  an  intelligible  cati:^e  of  co-ordi nation ^ 
we  are  required  to  suppose  that  such  a  happy  con- 
currence of  innumerable  independent  variations  must 
have  occurred  by  mere  accident — and  this  on  innu- 
merable different  occasions  in  the  bodies  of  as  many 
successive  ancestors  of  the  existing  species.  For  at 
each  successive  sta<^e  of  the  improvement  natural 
selection  (if  working  alor  :)  must  have  needed  all,  or 
at  any  rate  most,  of  the  co-ordinated  parts  to  occur  in 
the  same  individual  organisms  ^ 

In  alluding  to  what  I  have  already  published  upon 
the  difficulty  which  thus  appears  to  be  presented  to 
his  theory,  Weismann  says,  *'  At  no  distant  time  I  hope 
to  be  able  to  consider  this  objection,  and  to  show  that 
the  apparent  support  given  to  the  old  idea  [i.  e.  of  the 
transmission  of  functionally-produced  modifications] 
is  really  insecure,  and  breaks  down  as  soon  as  it  is 
critically  examined  V 

^  For  another  and  better  illustration  more   recently   published   by 
Mr.  Spencer,  see  The  Inadequacy  of  Natural  Selection,  p.  aa. 
"  Essays  on  Heredity,  vol.  i.  p.  3S9, 
[For  further  treatment  of  the  subject  under  discussion  see  Weismann, 
The  All-sujjuiciuy  of  Natural  Selection  (Conteinp.   Ker.    Sept.  and 

II.  F 


i 


\ 

i 


!J 


66 


Darwin,  and  after  Darwin. 


ni* 


ni 


I 


''a 


So  much  for  what  Weismann  has  said  touching  this 
natter.  But  the  matter  has  also  been  dealt  with  both 
by  Darwin  and  by  Wallace.  Darwin  very  properly 
distinguishes  between  the  fallacy  that  "  with  animals 
such  as  the  giraffe,  of  which  the  whole  structure  is 
admirably  co-ordinated  for  certain  purposes,  it  has 
been  supposed  that  all  the  parts  must  have  been 
simultaneously  modified  ^"  and  the  sound  argument 
that  the  co  ordination  itself  cannot  have  been  due  to 
natural  selection  alone.  This  important  distinction 
may  be  rendered  more  clear  as  follows. 

The  facts  of  artificial  selection  prove  that  immense 
modifications  of  structure  may  be  caused  by  a  cumu- 
lative blending  in  the  same  individuals  of  characters 
which  were  originally  distributed  among  different 
individuals.  Now,  in  the  parallel  case  of  natural 
selection  the  characters  thus  blended  will  usually — 
if  not  invariably — be  of  an  adaptive  kind  ;  and  their 
eventual  blending  together  in  the  same  individuals 
will  be  due  to  free  intercrossing  of  the  most  fit. 
But  this  blending  of  adaptations  is  quite  a  different 
matter  from  the  occurrence  of  co-ordination.  For 
it  belongs  to  the  essence  of  co-ordination  that  each 
of  the  co-ordinated  parts  should  be  destitute  of  adap- 
tive value  per  se  :  the  adaptation  only  begins  to  arise 
if  all  the  parts  in  question  occur  associated  together  in 
the  same  individuals  from  the  very  first.  In  this 
case  it  is  obvious  that  the  analogy  of  artificial  selec- 
tion can  be  of  no  avail  in  explaining  the  facts, 
since  the  difficulty  presented  has  nothing  to  do  with 

Oct.  1893),  and  The  Effect  of  External  Influences  upon  Development, 
*'  Romanes  Lecture  "  1894,  and  Spencer,  IVeisfnannism  once  more  (Cout. 
Rev.  Oct.  i894\    C.  LI.  M.j 
'   Variation,  6ic.,  vol.  ii.  p.  io6. 


Characters,  Hereditary  and  Acquired.    67 


the  blending  in  single  individuals  of  adaptations 
previously  distributed  among  different  individuals ; 
it  has  to  do  with  the  simultaneous  appearance  in 
single  individuals  of  a  co-adaptation  of  parts,  none 
of  which  could  ever  have  been  of  any  adaptive 
value  had  it  been  previously  distributed  among 
different  individuals.  Consequently,  where  Darwin 
comes  to  consider  this  particular  case  (or  the  case 
of  co-adaptation  as  distinguished  from  the  blending 
of  adaptations),  he  freely  invokes  the  aid  of  the 
Lamarckian  principles  ^ 

Wallace,  on  the  other  hand,  refuses  to  do  this,  and 
says  that  "the  best  answer  to  the  difficulty"  of  sup- 
posing natural  selection  to  have  been  the  only  cause 
of  co-adaptation  may  be  **  found  in  the  fi.  '  that 
the  very  thing  said  to  be  impossible  by  variation 
and  natural  selection,  has  been  again  and  again 
affected  by  variation  and  artificial  selection^."  This 
analogy  (which  Darwin  had  already  and  ver^  properly 
adduced  with  regard  to  the  blending  of  adaptations; 
he  enforces  by  special  illustrations  ;  but  he  does  not 
appear  to  perceive  that  it  misses  the  whole  and 
only  point  of  the  "difficulty"  against  which  it  is 
brought.  For  the  case  which  his  analogy  sustains 
is  not  that  which  Darwin,  Spencer,  Broca  and  others, 
mean  by  co-adaptation:  it  is  the  case  of  a  blending 
of  adaptations.  It  is  not  the  case  where  adaptation 
\s  first  initiated  in  spite  of  intercrossing,  by  a  fortuitous 
concurrence  of  variations  each  in  itself  being  with- 
out adaptive  value  :  it  is  the  case  where  adaptation 
is    afterwards    increased   by  means   of  intercrossing^ 

'  E.  g.  Orison  0/  Species,  p.  178. 
*  Darwinism,  p.  418. 

F    2 


m 


i  i 

""8 

IN. 

H 


':it' 


vj 


») 


'1 

•1 


68 


Dativin,  and  after  Darzvin. 


-I 


i 

h 

• '  »• 


s« 


through  the  blending  of  variations    each    of   which 
has  always  been  in  itself  of  adaptive  value. 

From  this  I  hope  it  will  be  apparent  that  the  only- 
way  in  which  the  "  difficulty  "  from  co-adaptation  can 
be  logically  met  by  the  ultra-Darwinian  school,  is  by 
denying  that  the  phenomenon  of  co-adaptation  (as 
distinguished  from  the  blending  of  adaptations)  is  ever 
to  be  really  met  with  in  organic  nature.  It  may  be 
argued  that  in  all  cases  where  co-adaptation  appears 
to  occur,  closer  examination  will  show  that  the  facts 
are  really  due  to  a  blending  of  adaptations.  The 
characters  A  +  B  +  C  +  D,  which  are  now  found  united 
in  the  same  organism,  and,  as  thus  united,  all.  c  inspiring 
to  a  common  end,  may  originally  have  been  distri- 
buted among  different  organisms,  where  <^hey  severally 
subserved  some  other  ends — or  possibly  the  same 
end,  though  in  a  less  efficient  manner.  Obviously, 
however,  in  this  case  their  subseq  cat  cjmbination 
in  the  same  organism  would  not  be  an  instance  of 
co-adaptation,  but  r.i'  '.-lyof  an  advantageous  blend- 
ing together  of  aiready  .xisting  adaptations.  This 
argument,  or  rejoinder,  has  in  point  of  fact  been 
adopted  by  Professor  Meldola,  he  believes  that  all 
cases  of  seeming  co-adaptation  are  thus  due  to  a 
mere  blending  of  adaptations  ^  Of  course,  if  this 
position   can    be    maintained,    the    whole    difficulty 

'  Nature,  vol.  xliii.  pp.  410,  55,7;  vol.  xliv.  pp.  7,  29.  I  say 
"adopted,"  because  I  had  objected  to  his  quotin;^;  the  analogy  of  artificial 
selection,  and  stated,  as  above,  that  the  only  w£.y  to  meet  Mr.  Spencer  s 
"  difficulty"  was  to  deny  the  fact  of  co-adaplation  as  ever  occurring  in 
any  case.  It  then  appeared  that  Professor  Meldola  agreed  with  r-"  hs  to 
this.  But  I  -lo  not  yet  understand  why,  if  such  were  his  view,  h,.  '  gan 
by  endorsiig  Mr.  Wallace's  analogy  from  artificial  selection — i.  e. 
confusing  the  case  of  co-adaptation  v/ith  that  of  the  blending  of  adapta- 
tions.    11  any  one  denies  the  fact  of  co-adaptation,  he  cannot  assist  his 


Characters,  Hereditary  and  Acquired,    69 

from  co-adaptation  would  lapse.  But  even  then  it 
would  lapse  on  the  ground  of  fact.  It  would  not 
have  been  overturned,  or  in  any  way  affected,  by 
Wallace's  argument  from  artificial  selection.  For,  in 
that  event,  no  such  argument  would  be  required,  and, 
if  adduced,  would  be  irrelevant,  since  no  one  has 
ever  alleged  that  there  is  any  difficulty  in  under- 
standing the  mere  confluence  of  adaptations  by  free- 
intercrossing  of  the  best  adapted. 

Now,  if  we  are  agreed  that  the  only  question  in  debate 
is  the  question  of  fact  whether  or  not  co-adaptation 
ever  occurs  in  nature,  it  appears  to  me  that  the  best 
field  for  debating  the  question  is  furnished  by  the 
phenomena  of  reflex  action.  I  can  well  perceive  that 
the  instances  adduced  by  Broca  and  Spencer  in  support 
of  their  common  argument — such  as  the  giraf  e,  the 
elk,  &c. — are  equivocal.  But  I  think  that  many 
instances  which  may  be  adduced  of  reflex  action  are 
much  more  to  the  point.  For  it  belongs  to  ihii  very- 
nature  of  reflex  action  that  it  cannot  ivork  unless 
all  parts  of  the  machinery  concerned  are  alrea.iy  pre- 
sent, and  already  co-ordinated,  in  the  same  organism. 
It  would  be  useless,  in  so  far  '  such  action  is  con 
cerned  if  the  afferent  and  effer  t  nerves,  the  nerve- 
centre,  and  the  mu.scles  organically  grouped,  together, 
were  not  all  present  from  the  very  first  in  the  same 
individuals,  and  from  the  ^-^y  first  were  not  co- 
ordinated as  a  definite  piece  ot  organic  machinery. 

With    respect   to    reflex    actions,   therefore,    it    is 
desirable  to  begin  by  pointing   out   bow  widely  the 

denial  by  arguing  the  totally  different  fact  that  adaptations  may  be 
blended  by  free  intercrossing  ;  ibr  this  latter  fact  has  \\t\*ix  been  ques- 
tioned, and  has  notlung  to  do  with  <<v'  one  which  he  engaged  in 
disputing. 


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adaptations  which  they  involve  differ  from  those  where 
no  manufacture,  so  to  speak,  of  special  machinery  is 
required.  Thus,  it  is  easy  to  understand  how  natural 
selection  alone  is  capable  of  gradually  accumulating 
congenital  variations  in  the  direction  of  protective 
colouring  ;  of  mimicry  ;  of  general  size,  form,  mutual 
correlation  of  parts  as  connected  with  superior  strength, 
flectness,  agility,  &c. ;  of  greater  or  less  development 
of  particular  parts,  such  as  legs,  wings,  tails,  &c.  For 
in  all  such  cases  the  adaptation  which  is  in  process  of 
accumulation  is  from  its  very  commencement  and 
throughout  each  of  its  subsequent  stages,  of  use  in 
the  struggle  for  existence.  And  inasmuch  as  all  the 
individuals  of  each  successive  generation  vary  round 
the  specific  mean  which  characterized  the  preceding 
generation,  there  will  -ilways  be  a  sufficient  number  of 
individuals  which  present  congenital  variations  of  the 
kind  required  for  natural  selection  to  seize  upon, 
without  danger  of  their  being  swamped  by  free  in- 
tercrossing— as  Mr.  Wallace  has  very  ably  shown  in 
hih  Darwinism.  But  this  law  of  averages  can  apply 
only  to  cases  where  single  structures — or  a  single 
group  of  correlated  structures — are  already  present, 
and  already  varying  round  a  specific  mean.  The  case 
is  quite  different  where  a  co-ordination  of  structures  is 
required  for  the  performance  oiz. previously  non-existent 
reflex  action.  For  some,  at  least,  of  these  structures 
must  be  new,  as  must  also  be  the  function  which  all  of 
them  first  conspire  to  perform.  Therefore,  neither  the 
new  elements  of  structure,  nor  the  new  combination  of 
structures,  can  have  been  previously  given  as  varying 
round  a  specific  mean.  On  the  contrary,  a  very 
dciinite  piece  of  machinery,  consisting  of  many  co- 


Characters,  Hereditary  and  Acquired.    71 


ordfnated  parts,  must  somehow  or  other  be  originated 
in  a  high  degree  of  working  efficiency,  before  it  can 
be  capable  of  answering  its  purpose  in  the  prompt 
performance  of  a  particular  action  under  particular 
circumstances  of  stimulation.  Lastly,  such  pieces  of 
machinery  are  always  of  a  highly  delicate  character, 
and  usually  involve  so  immensely  complex  a  co- 
ordination of  mutually  dependent  parts,  that  it  is  only 
a  physiologist  who  can  fully  appreciate  the  magnitude 
of  the  distinction  between  '*  adaptations  "  of  this  kind, 
and  'adaptations"  of  the  kind  which  arise  through 
natural  selection  seizing  upon  congenital  variations  as 
these  oscillate  round  a  specific  mean. 

Or  the  whole  argument  may  be  presented  in  another 
form,  under  three  different  headings,  thus  : — 

In  the  first  place,  it  will  be  evident  from  what  has 
just  been  said,  that  such  a  piece  of  machinery  as  is  con- 
cerned in  even  the  simplest  reflex  action  cannot  have 
occurred  in  any  considerable  number  of  individuals 
of  a  species,  when  it  first  began  to  be  constructed. 
On  the  contrary,  if  its  origin  were  dependent  on  con- 
genital variations  alone,  the  needful  co-adaptation  of 
parts  which  it  requires  can  scarcely  have  happened  to 
occur  in  more  than  a  very  small  percentage  of  cases — 
even  if  it  be  held  conceivable  that  by  such  means 
alone  it  should  ever  have  occurred  at  all.  Hence, 
instead  of  preservation  and  subsequent  improvement 
having  taken  place  in  consequence  of  free  intercrossing 
among  all  individuals  of  the  species  (as  in  the  cases 
of  protective  colouring,  &c.,  where  adaptation  has  no 
reference  to  any  mechanical  co-adaptation  of  parts), 
they  must  have  taken  place  i7i  spite  of  such  inter- 
crossing. 


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72         Darwin,  and  after  Darwin, 

In  the  second  place,  adaptations  due  to  organic 
machineries  of  this  kind  differ  in  another  all-important 
respect  from  those  due  to  a  summation  of  adaptive 
characters  which  are  already  present  and  already 
varying  round  a  specific  mean.  The  latter  depend  for 
their  summation  upon  the  fact — not  merely,  as  just 
stated,  that  they  are  already  present,  already  varying 
round  a  specific  mean,  and  therefore  owe  their  pro- 
gressive evolution  to  free  intercrossing,  but  also — that 
they  admit  of  very  different  degrees  of  adaptation.  It 
is  only  because  the  degree  of  adaptation  in  generation 
B  is  superior  to  that  in  generation  A  that  gradual 
improvement  in  respect  of  adaptation  is  here  possible. 
In  the  case  of  protective  resemblance,  for  example, 
a  very  imperfect  and  merely  accidental  resemblance 
to  a  leaf,  to  another  insect.  &c.,  may  at  the  first  start 
have  conferred  a  sufficient  degree  of  adaptive  imitation 
to  count  for  something  in  the  struggle  for  life  ;  and,  if 
so,  the  basis  would  be  given  for  a  progressive  building 
up  by  natural  selection  of  structures  and  colours 
in  ever-advancing  degrees  of  adaptive  resemblance. 
There  is  here  no  necessity  to  suppose — nor  in  point 
of  fact  is  it  ever  supposed,  since  the  supposition 
would  involve  nothing  short  of  a  miracle — ^that  such 
extreme  perfection  in  this  respect  as  we  now  so  fre- 
quently admire  has  originated  suddenly  in  a  single 
generation,  as  a  collective  variation  of  a  congenital 
kind  affecting  simultaneously  a  large  proportional 
number  of  individuals.  But  in  the  case  of  a  reflex 
mechanism — which  may  involve  even  greater  marvels 
of  adaptive  adjustment,  and  all  the  parts  of  which 
must  occur  in  the  same  individuals  to  be  of  any 
use — it   is  necessary  to  suppose  some  such  sudden 


l! 


CharaderSy  Hereditary  and  Acquired.    73 

and  collective  origin  in  some  very  high  degree  of 
efficiency,  if  natural  selection  has  been  the  only 
principle  concerned  in  afterwards  perfecting  the 
meciianism.  For  it  is  self-evident  that  a  reflex  action, 
from  its  very  nature,  cannot  admit  of  any  great 
differences  in  its  degrees  of  adaptation :  if  it  is  to 
work  at  all,  so  as  to  count  for  anything  in  the  struggle 
for  life,  it  must  already  be  given  in  a  state  of  working 
efficiency.  So  that,  unless  we  invoke  either  the 
doctrine  of  "prophetic  types  "or  the  theory  of  sudden 
creations,  I  confess  I  do  not  see  how  we  are  to  explain 
either  the  origin,  or  the  development,  of  a  reflex 
mechanism  by  means  of  natural  selection  alone. 

Lastly,  in  the  third  place,  even  when  reflex 
mechanisms  have  been  fully  formed,  it  is  often  beyond 
the  power  of  sober  credence  to  believe  that  they  now 
are,  or  ever  can  have  been,  of  selective  value  in  the 
struggle  for  existence,  as  I  will  show  further  on.  And 
such  cases  go  to  fortify  the  preceding  argument.  For 
if  not  conceivably  of  selective  value  even  when  com- 
pletely evolved,  much  less  can  they  conceivably  have 
been  so  through  all  the  stages  of  their  complex 
evolution  back  to  their  very  origin.  Therefore,  sup- 
posing for  the  present  that  there  are  such  cases  of 
reflex  action  in  nature,  neither  their  origin  nor  their 
development  can  conceivably  have  been  due  to 
natural  selection  alone.  The  Lamarckian  factors, 
however,  have  no  reference  to  degrees  of  adaptation, 
any  more  than  they  have  to  degrees  of  complexity. 
No  question  of  value,  as  selective  or  otherwise,  can 
obtain  in  their  case :  neither  in  their  case  does  any 
difficulty  obtain  as  regards  the  co-adaptatior.  of 
severally  useless  parts. 


i 

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■« 


74         Darwin,  and  after  Darwin. 

Now,  if  all    these  distinctions  between   the   Dar- 
winian   and    Lamarckian    prmciples   are   valid — and 
I  cannot  see  any  possibility  of  doubt  upon  this  point 
— strong  evidence   in  favour  of  the  latter  would  be 
furnished   by  cases  (if  any  occur)  where  structures, 
actions,   instincts,    &c. .   although   of  some   adaptive 
value,  arc  nevertheless  plainly  not  of  selective  value. 
According   to  the  ultra-Darwinian    theory,  no  such 
cases  ought  ever  to  occur :  according  to  the  theory 
of  Darwin  himself,  they  ought  frequently  to  occur. 
Therefore  a  good  test,  or  criterion,  as  between  these 
different  theories  of  organic  evolution  is  furnished  by 
putting  the  simple  question  of  fact — Can  we,  or  can 
we  not,  show  that  there  are  cases  of  adaptation  where 
the  degree  of  adaptation  is  so  small  as  to  be  incom- 
patible with  the  supposition  of  its  presenting  a  selective 
value?   And  if  we  put  the  wider  question — Are  there 
any  cases  where  the  co-adaptation  of  severally  useless 
parts   has  been  brought  about,  when    even    the   re- 
sulting whole  does  not  present  a  selective  value? — 
then,  of  course,  we  impose  a  still  more  rigid  test. 

Well,  notwithstanding  the  difficulty  of  proving  such 
a  negative  as  the  absence  of  natural  selection  where 
adaptive  development  is  concerned,  I  believe  that  there 
are  cases  which  conform  to  both  these  tests  simul- 
taneously ;  and,  moreover,  that  they  are  to  be  found  in 
most  abundance  where  the  theory  of  use-inheritance 
would  most  expect  them  to  occur — namely,  in  the 
province  of  reflex  action.  For  the  very  essence  of 
this  theory  is  the  doctrine,  that  constantly  associated 
use  of  the  same  parts  for  the  performance  of  the  same 
action  will  progressively  organize  those  parts  into 
a  reflex  mechanism — no  matter  how  high  a  degree  of 


Characters,  Hereditary  and  Acqiiiird.    75 


co-adaptation  may  thus  be  reached  on  the  one  hand, 
or  how  low  a  dej^rce  of  utilitarian  v.duc  on  the  other. 

Having  now  stated  the  general  or  abstract  prin- 
ciples which  I  ret^f.ud  as  constituting  a  defence  of 
the  Lamarckiar.  factors,  so  far  as  this  admits  of 
being  raised  on  grounds  of  physiology,  we  will  now 
consider  a  few  concrete  cases  by  way  of  il lustra- 
ion.  It  is  needless  to  multiply  such  cases  for  the 
mere  purpose  of  illustration.  For.  on  reading  those 
here  given,  every  physiologist  will  at  once  perceive 
that  they  might  be  added  to  indefinitely.  The 
point  to  observe  is,  the  relation  in  which  these 
samples  of  reflex  action  stand  to  the  general 
principles  in  question  ;  for  there  is  nothing  unusual 
in  the  samples  them.selves.  On  the  contrary,  they 
are  chosen  because  they  are  fairly  typical  of  the 
phenomena  of  reflex  action  in  general. 

In  our  own  organization  there  is  a  reflex  mechanism 
which  ensures  the  prompt  withdrawal  of  the  legs 
from  any  source  of  irritation  supplied  to  the  feet. 
For  instance,  even  after  a  man  has  broken  his  spine 
in  such  a  manner  as  totally  to  interrupt  the  func- 
tional continuity  of  his  spinal  cord  and  brain, 
the  reflex  mechanism  in  question  will  continue  to 
retract  his  legs  when  his  feet  are  stimulated  by 
a  touch,  a  burn,  &c.  This  responsive  action  is 
clearly  an  adaptive  action,  and,  as  the  man  neither 
feels  the  stimulati')n  nor  the  resulting  movement, 
it  is  as  clearly  a  reflex  action.  The  question  now  is 
as  to  the  mode  of  its  origin  and  development. 

I  will  not  here  dwell  upon  the  argument  from 
co-adaptation,  because  this  may  be  done  more 
effectually  in  the  case  of    more   complicated    reflex 


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actions,  but  will  ask  whether  we  can  reasonably 
hold  that  this  particular  reflex  action — comparatively 
simple  though  it  is — has  ever  been  of  selective 
value  to  the  human  species,  or  to  the  ancestors 
thereof?  Even  in  its  present  fully-formed  con- 
dition it  is  fairly  questionable  whether  it  is  of  any 
adaptive  value  at  all.  The  movement  performed  is 
no  doubt  an  adaptive  movement  \  but  is  there  any 
occasion  upon  which  the  reflex  mechanism  con- 
cerned therein  can  ever  have  been  of  adaptive  use} 
Until  a  man's  legs  have  been  paralyzed  as  to 
their  voluntary  motion,  he  will  always  promptly 
withdraw  his  feet  from  any  injurious  source  of 
irritation  by  means  of  his  conscious  intelligence. 
True,  the  reflex  mechanism  secures  an  almost  in- 
appreciable saving  in  the  time  of  response  to  a 
stimulus^  as  compared  with  the  time  required  for 
response  by  an  act  of  v^iW  ;  but  the  difference  is 
so  ejiceedingly  small,  that  we  can  hardly  suppose 
the  saving  of  it  in  this  particular  case  to  be 
a  matter  of  any  adaptive — much  less  selective 
— importance.  Nor  is  it  more  easy  to  suppose 
that  the  reflex  mechanism  has  been  developed  by 
natural  selection  for  the  purpose  of  replacing  volun- 
tary action  when  the  latter  has  been  destroyed  or 
suspended  by  grave  spinal  injury,  paralysis,  coma, 
or  even  ordinary  sleep.  In  short,  even  if  for  the 
sake  of  argument  we  allow  it  to  be  conceivable  that 
any  single  human  being,  ape,  or  still  more  distant 
ancestor,  has  ever  owed  its  life  to  the  possession  of 
this  mechanism,  we  may  still  be  certain  that  not  one 
in  a  million  can  have  done  so.  And,  if  this  is  the 
case   with   regard   to   the   mechanism   as  now  fully 


1 


Characters  J  Hereditary  and  Acquired.   77 


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constructed,  still  more  must  it  have  been  the  case 
with  regard  to  all  the  previous  sta^jes  of  construction. 
For  here,  without  elaborating  the  point,  it  would 
appear  that  a  process  of  construction  by  survival  of 
the  fittest  alone  is  incomprehensible. 

On  the  other  hand,  of  course,  the  theory  of  use- 
inheritance  furnishes  a  fully  intelligible — whether  or  not 
a  true — explanation.  For  those  nerve-centres  in  the 
spinal  cord  which  co-ordinate  the  muscles  required  for  ' 
retracting  the  feet  are  the  centres  used  by  the  will 
for  this  purpose.  And,  by  hypothesis,  the  frequent 
use  of  them  for  this  purpose  under  circumstances 
of  stimulation  which  render  the  muscular  response 
appropriate,  will  eventually  establish  an  organic 
connexion  between  such  response  and  the  kind  of 
stimulation  to  which  it  is  appropriate — even  though 
there  be  no  utilitarian  reason  for  its  establish- 
ment '.  To  invert  a  ^lirase  of  Aristotle,  we  do  not 
frequently  use  this  mechanism  because  we  have  it 
(seeing  that  in  our  normal  condition  there  is  no 
necessity  for  such  use) ;  but,  by  hypothesis,  we  have 
it  because  we  have  frequently  used  its  several  elements 
in  appropriate  combination. 

I  will  adduce  but  one  further  example  in  illustra- 
tion of  these  general  principles — passing  at  once 
from  the  foregoing  case  of  comparative  simplicity 
to  one  of  extreme  complexity. 

There  is  a  well-known  experiment  on  a  brainless 
frog,  which  reveals  a  beautiful  reflex  mechanism  in 

*  It  may  be  said,  with  regard  to  this  particular  reflex,  that  it  may 
perhaps  be,  so  to  speak,  a  mechanical  accident,  arising  from  the 
contigaity  of  the  sensory  and  motor  roots  in  the  cord.  But  as  this 
suggestion  cannot  apply  to  other  reflexes  presently  to  be  adduced,  it  need 
not  be  considered. 


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Darwin f  and  after  Darwin, 


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the  animal,  whereby  the  whole  body  is  enabled  con- 
tinually to  readjust  its  balance  on   a  book   (or   any 
other  plane    surface),   as   this  is    slowly   rotated   on 
a  horizontal  axis.     So  long  as  the  book  is  lying  flat, 
the  frog  remains  motionless  ;  but  as  soon  as  the  book 
is  tilted  a  little,  so  that  the  frog   is   in   danger    of 
slipping  off,  all  the  four  feet  begin  to  crawl  up  the 
hill ;    and  the  steeper   the   hill   becomes,  the   faster 
they  crawl.     When   the   book   is   vertical,  the  frog 
has    reached    the   now  horizontal  back,  and  so   on. 
Such  being  the  facts,  the  question  is — How  can  the 
complicated  piece  of  machinery  thus  implied  have 
been  developed  by  natural  selection?     Obviously  it 
cannot  have  been  so  by  any  of  the  parts  concerned 
having   been  originally   distributed    among   different 
individuals,  and  afterwards  united  in  single  individuals 
by  survival  (i.e.   free   intercrossing)    of    the    fittest. 
In  other  words,  the  case  is  obviously  one  of  co-adap- 
tation, and  not  one  of  the  blending  of  adaptations. 
Again,  and  no  less  obviously,  it  is   impossible  that 
the  co-adaptation  can  have  been  gradually  developed 
by  natural  selection,  because,  in  order  to  have  been 
so,  it  must  by  hypothesis  have  been  of  some  degree 
of  use   in   every  one   of  its   stages ;  yet   it   plainly 
cannot  have  been   until  it  had  been  fully  perfected 
in  all  its  astonishing  complexity  ^ 


*  Of  course  it  will  be  observed  that  the  question  is  not  with  regard 
to  the  development  of  all  tlie  nerves  and  muscles  concerned  in  this 
particular  process.  It  is  as  to  the  development  of  the  co-ordinating 
centres,  which  thus  so  delicately  respond  to  the  special  stimuli  furnished 
by  variations  of  angle  to  the  horizon.  And  it  is  as  inconceivable  in  this 
case  of  reflex  action,  as  it  is  in  almost  every  other  case  of  reflex  action, 
that  the  highly  specialized  machinery  required  for  performing  the  adaptive 
function  can  ever  have  had  its  origin  in  the  performance  of  any  other 


Characters,  Hereditary  and  Acquired.    79 


Las'^ly,  not  only  does  it  thus  appear  impossible 
that  during  all  stages  of  its  development — or  while 
as  yet  incapable  of  performing  its  intricate  fimction — 
this  nascent  mechanism  can  have  had  any  adaptive 
value  ;  but  even  as  now  fully  developed,  who  will 
venture  to  maintain  that  it  presents  any  selective 
value?  As  long  as  the  animal  preserves  its  brain, 
it  will  likewise  preserve  its  balance,  by  the  exercise 
of  its  intelligent  volition.  And,  if  the  brain  were 
in  some  way  destroyed,  the  animal  would  be 
unable  to  breed,  or  even  to  feed  ;  so  that  natural 
selection  can  never  have  had  any  opportunity^  so 
to  speak,  of  developing  this  reflex  mechanism  in 
brainless  frogs.  On  the  other  hand,  as  we  have  just 
seen,  we  cannot  perceive  how  there  can  ever  have 
been  any  raison  d'etre  for  its  development  in  normal 
frogs — even  if  its  development  were  conceivably 
possible  by  means  of  this  agency.  But  if  practice 
makes  perfect  in  the  race,  as  it  does  in  the  individual, 
we  can  immediately  perceive  that  the  constant  habit 
of  correctly  adjusting  its  balance  may  have  gradually 
developed,  in  the  batrachian  organization,  this  non- 
necessary  reflex  ^ 


^ 


5 


function.  Indeed,  a  noticeable  peculiarity  of  reflex  mechanisms  as  a  class 
is  the  highly  specialized  character  of  the  fonctions  which  their  highly 
organized  structures  subserve. 

'  We  meet  with  a  closely  analogous  reflex  mechanism  in  brainless 
vertebrata  of  other  kinds ;  but  these  do  not  furnish  such  good  test  cases, 
because  the  possibility  of  natural  selection  cannot  be  so  efficiently 
attenuated.  The  perching  of  brainless  birds,  for  instance,  at  once  refers 
us  to  the  roosting  of  sleeping  birds,  where  the  reflex  mechanism 
concerned  is  clearly  of  high  adaptive  value.  I'hcrefore  such  a  case  is 
not  available  as  a  test,  although  the  probability  is  that  birds  have 
inherited  their  balancing  mechanisms  from  their  sauropsidian  ancestors, 
where  it  would  have  been  of  no  such  adaptive  importance. 


I 


8o  Darwin  J  and  after  Darwin. 


y 


J;; 

!;■' 


.11 


•ill 


And,  of  course,  this  example — like  that  of  with- 
drawing the  feet  from  a  source  of  stimulation,  which 
a  frog  will  do  as  well  as  a  man— does  not  stand  alone. 
Without  going  further  a-field  than  this  same  animal, 
any  one  who  reads,  from  our  present  point  of  view, 
Goltz's  work  on  the  reflex  actions  of  the  frog,  will 
find  that  the  great  majority  of  them — complex  and 
refined  though  most  of  them  are — cannot  conceivably 
have  ever  been  of  any  use  to  any  frog  that  was  in 
undisturbed  possession  of  its  brain. 

Hence,  not  to  occupy  space  with  a  reiteration  of 
facts  all  more  or  less  of  the  same  general  kind, 
and  therefore  all  presenting  identical  difficulties  to 
ultra-Darwinian  theory,  I  shall  proceed  to  give  two 
others  which  appear  to  me  of  particular  interest  in 
the  present  connexion,  because  they  furnish  illus- 
trations of  reflex  actions  in  a  state  of  only  partial 
development,  and  are  therefore  at  the  present  moment 
demonstrably  useless  to  the  animal  which  displays 
them. 

Many  of  our  domesticated  dogs,  when  we  gently 
scratch  their  sides  and  certain  other  parts  of  the  body, 
will  themselves  perform  scratching  movements  with 
the  hind  leg  of  the  same  side  as  that  upon  which  the 
irritation  is  being  supplied.  According  to  Goltz  *, 
this  action  is  a  true  reflex ;  for  he  found  that  it  is 
performed  equally  well  in  a  dog  which  has  been 
deprived  of  its  cerebral  hemispheres,  and  therefore 
of  its  normal  volition.     Again,  according  to  Haycraft'*, 

*  PJlugirs  Archiv,  Bd.  xx.  s.  23  (1879). 

•  Brain,  part  xlviii,  pp.  516-19  (1889). — There  is  still  better  proof 
of  this  in  the  case  of  certain  rodents.  For  instance,  observing  that  rats 
and  mice  are  under  the  necessity  of  very  frequently  scratching  themselves 
with  their  hind-feet,  I  tried  the  experiment  of  removing  the  latter  from 


I 


itly 

)dy, 
rith 
Itht 
Cz^ 
is 
;en 
lore 


Characters,  Hereditary  and  Acquired.   81 

this  reflex  is  congenital,  or  not  acquired  during  the 
life-time  of  each  individual  dog.  Now.  although  the 
action  of  scratching  is  doubtless  adaptive,  it  appears 
to  me  incredible  that  it  could  ever  have  become 
organized  into  a  congenital  reflex  by  natural  selec- 
tion. For,  in  order  that  it  should,  the  scratching 
away  fleas  would  require  to  have  been  a  function  of 
selective  value.  Yet,  even  if  the  irritation  caused  by 
fleas  were  supposed  to  be  so  far  fatal  in  the  struggle 
for  existence,  it  is  certain  that  they  would  always  be 
scratched  away  by  the  conscious  intelligence  of  each 
individual  dog ;  and,  therefore,  that  no  advantage 
could  be  gained  by  organizing  the  action  into  a 
reflex.  On  the  other  hand,  if  acquired  characters 
are  ever  in  any  degree  transmitted,  it  is  easy  to 
understand  how  so  frequently  repeated  an  action 
should  have  become,  in  numberless  generations  of 
dogs,  congenitally  automatic. 

So  much  for  the  general  principle  of  selective 
value  as  applied  to  this  particular  case.  And  simi- 
larly, of  course,  we  might  here  repeat  the  application 

newly-born  individuals — i.  e.  before  the  animals  were  able  to  co-ordinate 
their  movements,  and  therefore  before  they  had  ever  even  attempted  to 
scratch  themselves.  Notwithstanding  that  they  were  thus  destitute  of 
individual  experience  with  regard  to  the  benefit  of  scratching,  they  began 
their  scratching  movements  with  their  stumps  as  soon  as  they  were 
capable  of  executing  co-ordinated  movements,  and  afterwards  continued 
to  do  so  till  the  end  of  their  lives  with  as  much  vigour  and  frequency  as 
nnmutilated  animals.  Although  the  stumps  could  not  reach  the  scats 
of  irritation  which  were  bent  towards  them,  they  used  to  move  rapidly 
in  the  air  for  a  time  sufficient  to  have  given  the  itching  part  a  good 
scratch,  had  the  feet  been  present — after  which  the  animals  would  resume 
their  sundry  other  avocations  with  apparent  satisfaction.  These  facta 
showed  the  hereditary  response  to  irritation  by  parasites  to  be  so  strong, 
that  even  a  whole  life-time's  experience  of  its  futility  made  no  difference 
in  the  frequency  or  the  vigour  thereof. 

II.  G 


m 
\ 


1 


■ 


'..li 


'm^ 


\ 


r 

* '. 

I . 

% 

)>  ::■: 
It 


;  ■"' 


¥l! 


: 


82  Darwin,  and  after  Darwin. 

of  all  the  other  p^eneral  principles,  which  have  just 
been  applied  in  the  two  preceding  cases.  But  it  is 
only  one  of  these  other  general  principles  which 
I  desire  in  the  present  case  specially  to  consider, 
for  the  purpose  of  considering  more  closely  than 
hitherto  the  difficulty  which  this  principle  presents 
to  ultra-Darwinian  theory. 

The  difficulty  to  which  I  allude  is  that  of  under- 
standing how  all  the  stages  in  the  development  of 
a  reflex  action  can  have  been  due  to  natural  selection, 
seeing  that,  before  the  reflex  mechanism  has  been 
sufficiently  elaborated  to,  perform  its  function,  it  can- 
not have  presented  any  degree  of  utility.  Now  the 
particular  force  of  the  present  example,  the  action 
of  scratching — as  also  of  the  one  to  follow — cor.sists 
in  the  fact  that  it  is  a  case  where  a  reflex  action  is 
not  yet  completely  organized.  It  appears  to  be  only 
in  course  of  construction,  so  that  it  is  neither  in- 
variably present,  nor,  when  it  is  present,  is  it  ever 
fully  adapted  to  the  performance  of  its  function. 

That  it  is  not  invariably  present  (when  the  brain 
is  so)  may  be  proved  by  trying  the  simple  experi- 
ment on  a  number  of  puppies — and  also  of  full- 
grown  dogs.  Again,  that  even  when  it  is  present 
it  is  far  from  being  fully  adapted  to  the  perform- 
ance of  its  function,  may  be  proved  by  observing 
that  only  in  rare  instances  does  the  scratching 
leg  succeed  in  scratching  the  place  which  is  being 
irritated.  The  movements  are  made  more  or  less  at 
random,  and  as  often  as  not  the  foot  fails  to  touch 
the  body  at  any  place  at  all.  Hence,  although  we 
have  a  "prophecy"  of  a  reflex  action  well  designed 
for  the  discharge  of  a  particular  function,  at  present 


Characters,  Hereditary  and  Acquired.    83 


!ing 
s  at 
uch 
we 
ned 
>ent 


the  machinery  is  not  sufficiently  perfected  for  the 
adequate  discharge  of  that  function.  In  this  impor- 
tant respect  it  differs  from  the  otherwise  closely 
analogous  reflex  action  of  the  frog,  whereby  the 
foot  of  the  hind  leg  is  enabled  to  localize  with 
precision  a  seat  of  irritation  on  the  side  of  the 
body.  But  this  beautiful  mechanism  in  the  frog  can- 
not have  sprung  into  existence  ready  formed  at  any 
historical  moment  in  the  past  history  of  the  phyla. 
It  must  have  been  the  subject  of  a  more  or  hss 
prolonged  evolution,  in  some  stage  of  which  it  must 
presumably  have  resembled  the  now  nascent  scratch- 
ing reflex  of  the  dog,  in  making  merely  abortive 
attempts  at  localizing  the  seat  of  irritation — supposing 
of  course,  that  some  physiologist  had  been  there  to 
try  the  experiment  by  first  removing  the  brain. 
Now,  even  if  one  could  imagine  it  to  be,  either  in  the 
frog  or  in  the  dog,  a  matter  of  selective  importance  that 
so  exceedingly  refined  a  mechanism  should  have  been 
developed  for  the  sole  purpose  of  inhibiting  the  bites 
of  parasites — which  in  every  normal  animal  would 
certainly  be  discharged  by  an  intentional  performance 
of  the  movements  in  question, — even  if,  in  order  to 
save  an  hypothesis  at  all  costs,  we  make  so  violent 
a  supposition  as  this,  still  we  should  do  so  in  vain. 
For  it  would  still  remain  undeniably  certain  that 
the  reflex  mechanism  is  not  of  any  selective  value. 
Even  now  the  mechanism  in  the  dog  is  not  sufficiently 
precise  to  subserve  the  only  function  which  occasionally 
and  abortively  it  attempts  to  perform.  Thus  it  has 
all  the  appearance  of  being  but  an  imitating  shadow 
of  certain  neuro-muscular  adjustments,  which  have 
been  habitually  performed  in  the  canine  phyla  by  a 

G    2 


*J 


"  'I 

'"J 

"Ik 


84 


Darwin^  and  after  Darwin, 


I 


<ltl 
mi 


If! 
'.I 

I- 


I 


■%\ 


w 


i*^ 


•hi: 


w 


volitional  response  to  cutaneous  irritation.  Were 
it  necessary,  this  argument  might  be  strengthened 
by  observing  that  the  reflex  action  is  positively 
Unproved  by  removal  of  the  brain. 

The  second  example  of  a  nascent  reflex  in  dogs 
which  I  have  to  mention  is  as  follows. 

Goltz  found  that  his  brainless  dogs,  when  wetted 
with  water,  would  shake  themselves  as  dry  as  po.ssible, 
in  just  the  same  way  as  normal  dogs  will  do  under 
similar  circumstances.  This,  of  course,  proves  that 
the  shaking  movements  may  be  performed  by  a 
reflex  mechanism,  which  can  have  no  other  function 
to  perform  in  the  organization  of  a  dog,  and  which, 
besides  being  of  a  highly  elaborate  character,  will 
respond  only  to  a  very  special  kind  of  stimulation. 
Now,  here  also  I  find  that  the  mechanism  is  con- 
genital, or  not  acquired  by  individual  experience. 
For  the  puppies  on  which  I  experimented  were  kept 
indoors  from  the  time  of  their  birth — so  as  never 
to  have  had  any  experience  of  being  wetted  by  rain, 
&c. — till  they  were  old  enough  to  run  about  with 
a  full  power  of  co-ordinating  their  general  movements. 
If  these  young  animals  were  suddenly  plunged  into 
water,  the  shock  proved  too  great :  they  would 
merely  lie  and  shiver.  But  if  their  feet  alone  were 
wetted,  by  being  dipped  in  a  basin  of  water,  the 
puppies  would  soon  afterwards  shake  their  heads  in 
the  peculiar  manner  which  is  required  for  shaking 
water  ofT  the  ears,  and  which  in  adult  dogs  consti- 
tutes the  first  phase  of  a  general  shaking  of  the 
whole  body. 

Here,  then,  we  seem  to  have  good  evidence  of  all 
the  same  facts  which  were  presented  in  the  case  of  the 


i 


)f  all 
If  the 


Characters,  Hereditary  and  Acquired.  85 

scratching  reflex.  In  the  first  place,  co-adaptation 
is  present  in  a  very  high  degree,  because  this  shaking 
reflex  in  the  dog.  unlike  tlie  skin-twitching  reflex 
in  the  horse,  docs  not  involve  only  a  single  muscle, 
or  even  a  single  group  of  muscles  :  it  involves  more 
or  less  the  co-ordinated  activity  of  many  voluntary 
muscles  all  over  the  body.  Such,  at  any  rate,  is 
the  case  when  the  action  is  performed  by  the  in- 
telligent volition  of  an  adult  dog ;  and  if  a  brainless 
dog,  or  a  young  puppy,  does  not  perform  it  so 
extensively  or  so  vigorously,  this  only  goes  to  prove 
that  the  reflex  h  s  not  yet  been  sufficiently  developed 
to  serve  as  a  substitute  for  intelligent  volition — i.e. 
that  it  is  useless,  or  a  mere  organic  shadow  of  the 
really  adaptive  substance.  Again,  even  if  this  nascent 
reflex  had  been  so  far  developed  as  to  have  been 
capable  of  superseding  voluntary  action,  still  we  may 
fairly  doubt  whether  it  could  have  proved  of  selective 
value.  For  it  is  questionable  whether  the  imme- 
diate riddance  of  water  after  a  wetting  is  a  matter 
of  life  and  death  to  dogs  in  a  state  of  nature. 
Moreover,  even  if  it  were,  every  individual  dog  would 
always  have  got  rid  of  the  irritation,  and  so  of 
the  dancjer,  by  means  of  a  voluntary  shake — with 
the  double  result  that  natural  selection  has  never 
had  any  opportunity  of  gradually  building  up 
a  special  reflex  mechanism  for  the  purpose  of 
securing  a  shake,  and  that  the  canine  race  have 
not  had  to  wait  for  any  such  unnecessary  process. 
Lastly,  such  a  process,  besides  being  unnecessary, 
must  surely  have  been,  under  any  circumstances, 
impossible.  For  even  if  we  were  to  suppose — again 
for    the     sake    of    saving    an    hypothesis    at    any 


'I 

•I, « 

♦I 

'«.  m 

•J  8 


Ml 


#> 
Ul 


•4 
if** 


If 


«t 


*i| 


311 


«l 


1^ 


86  Danvin,  and  after  Da  num. 

cost — that  the  presence  of  a  fully-formed  shaking 
reflex  is  of  selective  value  in  the  stru^^le  for  exist- 
ence, it  is  perfectly  certain  that  all  the  stafjes 
through  which  the  construction  of  so  elaborate  a 
mechanism  must  have  passed  could  not  have  been, 
under  any  circumstances,  of  any  such  value. 

But,  it  is  needless  to  repeat,  according  to  the 
hypothesis  of  use-inheritance,  there  is  no  necessity 
to  suppose  that  these  incipient  reflex  mechanisms 
are  of  any  value.  If  function  produces  structure  in 
the  race  as  it  does  in  the  individual,  the  voluntary 
and  frequently  repeated  actions  of  scratching  and 
shaking  may  very  well  have  led  to  an  organic 
integration  of  the  neuro-muscular  mechanisms  con- 
cerned. Their  various  parts  having  been  always 
co-ordinated  for  the  performance  of  these  actions  by 
the  intelligence  of  innumerable  dogs  in  the  past, 
Iheir  co-adapted  activity  in  their  now  automatic 
responses  to  appropriate  stimuli  presents  no  difficulty. 
And  the  consideration  that  neither  in  their  prospec- 
tively more  fully  developed  condition,  nor,  a  fortiori^ 
in  their  present  and  all  previous  stages  of  evolution, 
can  these  reflex  mechanisms  be  regarded  as  present- 
ing any  selective — or  even  so  much  as  any  adaptive 
— value,  is  neither  more  nor  less  than  the  theory  of 
use-inheritance  would  expect. 

Thus,  with  regard  to  the  phenomena  of  reflex  action 
in  general,  all  the  facts  are  such  as  this  theory  requires, 
while  many  of  the  tacts  are  such  as  the  theory  of 
natural  selection  alone  cannot  conceivably  explain. 
Indeed,  it  is  scarcely  too  much  to  say,  that  most 
of  the  facts  are  such  as  directly  contradict  the  latter 
theory    in    its    application    to   them.     But,    be    this 


Characters,  Hereditary  and  Acquired.  87 


as  it  may,  at  present  there  are  only  two  hypo- 
theses in  the  field  whereby  to  account  for  the  facts 
of  adaptive  evolution.  One  of  these  hypotheses 
is  universally  accepted,  and  the  only  question  Is 
whether  wc  are  to  rcfjaid  it  as  aloue  sufficient  to  ex- 
plain all  the  facts.  The  ether  hypothesis  having  been 
questioned,  we  can  test  its  validity  only  by  finding 
cases  which  it  is  fully  capable  of  explaining,  and 
which  do  not  admit  of  being  explained  by  its  com- 
panion hypothesis.  I  have  endeavoured  to  show 
that  we  have  a  large  class  of  such  cases  in  the 
domain  of  reflex  action,  and  shall  next  endeavour  to 
show  that  there  is  another  large  class  in  the  domain 
of  instinct. 

If  instinct  be,  as  Professor  Hering,  Mr.  Samuel 
Butler,  and  others  have  argued,  "  hereditary  habit  "— 
i.  e.  if  it  comprises  an  element  of  transmitted  ex- 
perience— we  at  once  find  a  complete  explanation  of 
many  cases  of  the  display  of  instinct  which  otherwise 
remain  inexplicable.  For  although  a  large  number — 
or  even,  as  I  believe,  a  large  majority — of  instincts 
are  explicable  by  the  theory  of  natural  selection  alone, 
or  by  supposing  that  they  were  gradually  developed 
by  the  survival  of  fortuitous  variations  in  the  way  of 
advantageous  psychological  peculiarities,  this  only 
applies  to  comparatively  simple  instincts,  such  as  that 
of  a  protectively  coloured  animal  exhibiting  a  prefer- 
ence for  the  surroundings  which  it  resembles,  or  even 
adopting  attitudes  in  imitation  of  objects  which  occur 
in  such  surroundings.  But  in  all  cases  where  instincts 
become  complex  and  refined,  we  seem  almost  com- 
pelled to  accept  Darwin's  view  that  their  origin  is  to 


Ml 


'I, 


'S  • 

■•'3 


88  Darwifif  and  after  Darwin. 


.1,:! 


*! 


■  ': 


be  sought  in  consciously  intelligent  adjustments  on 
the  part  of  ancestors. 

Thus,  to  give  only  one  example,  a  species  of 
Sphex  preys  upon  caterpillars,  which  it  stings  in 
their  nerve-centres  for  the  purpose  of  paralyzing, 
without  killing  them.  The  victims,  when  thus  ren- 
dered motionless,  are  then  buried  with  the  eggs  of 
the  Sphex,  in  order  to  serve  as  food  for  her  larvae 
which  subsequently  develop  from  these  eggs.  Now, 
in  order  thus  to  paralyze  a  caterpillar,  the  ophex  has 
to  sting  it  successively  in  nine  minute  and  particular 
points  along  the  ventral  surface  of  the  animal — and 
this  the  Sphex  unerringly  doec,  to  the  exclusion 
of  all  other  points  of  the  caterpillar's  anatomy.  Well, 
such  being  the  facts — according  to  M.  Fabre,  who 
appears  to  have  observed  them  carefully — it  is  con- 
ceivable enough,  as  Darwin  supposed  \  that  the 
ancestors  of  the  Sphex,  being  like  many  other  hymen- 
opterous  insects  highly  intelligent,  should  have 
observed  that  on  stinging  caterpillars  in  these  particular 
spots  a  greater  amount  of  effect  was  produced  than 
could  be  produced  by  stinging  them  anywhere  else ; 
and,  therefore,  that  they  habitually  stung  the  cater- 
pillars in  these  places  only,  till,  in  course  of  time,  this 
c  Iginally  intelligent  habit  became  by  heredity  instinc- 
tive. But  now,  on  the  other  hand,  if  we  exclude  the 
possibility  of  this  explanation,  it  appears  to  me  in- 
credible that  such  an  instinct  should  ever  have  been 
evolved  at  all ;  for  it  appears  to  me  incredible  that 
natural  selection,  unaided  by  originally  intelligent 
action,  could  ever  have  developed  such  an  instinct 


^  For  details  of  his  explanation  of  this  particular  case,  for  which 
I  particularly  inquired,  see  Mtntai  Evolution  in  AnimcUs,  pp.  301-a. 


"Y 


Characters y  Hereditary  and  Acquired.  89 

out  of  merely  fortuitous  variations — there  being,  by- 
hypothesis,  nothing  to  determine  variations  of  an 
insect's  mind  in  the  direction  of  stinging  caterpillars 
only  in  these  nine  intensely  localized  spots  ^ 

Again,  there  are  not  a  few  instincts  which  appe&r 
to  be  wholly  useless  to  their  possessors,  and  others 
again  which  appear  to  be  even  deleterious.  The 
dusting  over  of  their  excrement  by  certain  freely- 
roaming  carnivora ;  the  choice  by  certain  herbivora 
of  particular  places  on  which  to  void  their  urine,  or 
in  which  to  die ;  the  howling  of  wolves  at  the  moon  ; 
purring  of  cats,  &c.,  under  pleasurable  emotion ;  and 
sundry  other  hereditary  actions  of  the  same  appar- 
ently unmeaning  kind,  all  admit  of  being  readily 
accounted  for  as  useless  habits  originally  acquired 
in  various  ways,  and  afterwards  perpetuated  by 
heredity,  because  not  sufficiently  deleterious  to  have 
been  stamped  out  by  natural  selection  ^.  But  it  does 
not  seem  possible  to  explain  them  by  survival  of  the 
fittest  in  the  struggle  for  existence. 

Finally,  in  the  case  of  our  own  species,  it  is  self- 
evident  that  the  aesthetic,  moral,  and  religious  instincts 
admit  of  a  natural  and  easy  explanation  on  the 
hypothesis  of  use-inhericance,  while  such  is  by  no 
means  the  case  if  that  hypothesis  is  rejected.  Our 
emotions  of  the  ludicirous,  of  the  beautifui,  and  of  the 
sublime,  appear  to  be  of  the  nature  of  hereditary 
instincts ;  and  be  this  as  it  may,  it  v/ould  further 
appear  that,  whatever  else  they  may  be,  they  are 
certainly  not    of  a  life-preserving    character.    And 

»  Note  B. 

*  For  fuller  treatment  see  Mental  Evolution  in  Animals^  pp.  374-285, 
378-379*  381-383. 


r,' 


i';  If 

\ 


90  DarwiUj  and  after  Daruin. 


Y  ■  r  \ 


;.»i 


although  this  cannot  be  said  of  the  moral  sense  when 
the  theory  of  natural  selection  is  extended  from  the 
individual  to  the  tribe,  still,  when  we  remember  the 
extraordinary  complexity  and  refinement  to  which 
they  have  attained  in  civilized  man,  we  may  well 
doubt  whether  they  can  have  been  due  to  natural 
selection  alone.  But  space  forbids  discussion  of  this 
large  and  important  question  on  the  present  occasion. 
Suffice  it  therefore  to  say,  that  I  doubt  not  Weismann 
himself  would  be  the  first  to  allow  that  his  theory  of 
heredity  encounters  greater  difficulties  in  the  domain 
of  ethics  than  in  any  other — unless,  indeed,  it  be  that 
of  religion  ^ 


% 


I  have  now  given  a  brief  sketch  of  the  indirect 
evidence  in  favour  of  the  so-called  Lam arckian  factors, 
in  so  far  as  this  appears  fp.iiiy  deducible  from  the 
facts  of  reflex  action  and  of  instinct.  It  will  now  be 
my  endeavour  to  present  as  briefly  what  has  to  be  said 
against  this  evidence. 

As  previously  observed,  the  facts  of  reflex  action 
have  not  been  hitherto  adduced  in  the  present  con- 
nexion. This  has  led  me  to  occupy  considerably 
more  space  in  the  treatment  of  them  than  those  of 
instinct.  On  this  account,  also,  there  is  here  nothing 
to  quote,  or  to  consider,  per  contra.  On  the  other 
hand,  however,  Weismaim  i^.as  himself  dealt  with  the 
phenomena  of  instinct  in  animrJs,  though  not,  I  think, 
in  man — if  we  except  his  brilliant,  essay  on  music. 
Therefore    let   us   now    begin   this    division   of   our 

'  For  an  excellent  essay  on  the  deleterious  character  of  early  forms  of 
religion  from  a  biological  point  of  view,  see  the  Hon.  Lidy  Welby,  An 
Apparent  Paradox  in  Mental  Evolution  (Journ.  Anthrop.  Inst.  May  1891). 


■I  ,' 


Characters,  Hereditary  and  Acquired.   91 

subject  by  briefly  stating,  and  considering,  what  he 
has  said  upon  the  subject. 

The  answer  of  Wcismann  to  difficulties  which  arise 
against  the  ultra-Darwinian  theory  in  the  domain  of 
instinct,  is  as  follows : — 

"  The  necessity  for  extreme  caution  in  appealing  to  the  sup- 
posed hereditary  effects  of  use,  is  well  shown  in  the  case  of  those 
numerous  instincts  which  only  come  into  play  once  in  a  life-time, 
and  which  do  not  therefore  admit  of  improvement  by  practice. 
The  queen-bee  takes  her  nuptial  flight  only  once,  and  yet  how 
many  and  complex  are  the  instincts  and  the  reflex  mechanisms 
which  come  into  play  on  that  occasion.  Again,  in  many  insects 
the  deposition  of  eggs  occurs  but  once  in  a  life-time,  and  yet 
such  insects  always  fulfil  the  necessary  conditions  with  unfailing 
accuracy 


\k 


I » 


But  in  this  rejoinder  the  possibility  is  forgotten, 
that  although  such  actions  «re  now  performed  only 
once  in  the  individual  life-time,  originally — i.  e.  when 
the  instincts  were  being  developed  in  a  remote 
ancestry — they  may  have  been  performed  on  many 
frequent  and  successive  occasions  during  the  individual 
life-time.  In  all  the  cases  quoted  by  Weismann, 
instincts  of  the  kind  in  question  bear  independent 
evidence  of  high  antiquity,  by  occurring  in  whole 
genera  (or  even  families),  by  being  associated  with 
peculiar  and  often  highly  evolved  structures  required 
for  their  performance,  and  so  on.  Consequently,  in 
these  cases  ample  time  has  been  allowed  for  subse- 
quent changes  of  habit,  and  of  seasonal  alterations 
with  respect  to  propagation — both  these  things  being 
of  frequent  and  facile  occurrence  among  animals  of  all 
kinds,  even  within    periods  which  fall   under  actual 


.^,' 


;i 


'J,  • 

hit  4 

.J, 


'  Kssays,  i.  p.  93. 


9a 


Darwin^  and  after  Darwin, 


III 


if 

I* 


>• 


>v 


! 


I -ft 


4 


observation.  Nevertheless,  I  do  not  question  that 
there  are  instinctive  activities  which,  as  far  as  we  are 
able  to  see,  can  never  have  been  performed  more 
than  once  in  each  individual  life  time  ^  The  fact, 
however,  only  goes  to  show  what  is  fully  admitted — 
that  some  instincts  (and  even  highly  complex  instincts) 
have  apparently  been  developed  by  natural  selection 
alone.  Which,  of  course,  is  not  equivalent  to  showing 
that  all  instincts  must  have  been  developed  by  natural 
selection  alone.  The  issue  is  not  to  be  debated  on 
general  grounds  like  this,  but  on  those  of  particular 
cases.  Even  i^"  it  were  satisfactorily  proved  that  the 
instincts  of  a  queen-bee  have  been  developed  by 
natural  selection,  it  would  not  thereby  be  proved 
that  such  has  been  the  case  with  the  instincts  of 
a  Sphex  wasp.  One  can  very  well  understand  how 
the  nuptial  flight  of  the  former,  with  all  its  associated 
actions,  may  have  been  brought  about  by  natural 
selection  alone ;  but  this  does  not  help  us  to  under- 
stand how  the  peculiar  instincts  of  the  latter  can  have 
been  thus  caused. 

Strong  evidence  in  favour  of  Weismann's  views 
does,  however,  at  first  sight  seem  to  be  furnished  by 
social  hymenoptera  in  other  respects.  For  not  only 
does  the  queen  present  highly  specialized  and  alto- 
gether remarkable  instincts  ;  but  the  neuters  present 
totally  different  and  even  still  more  remarkable 
instincts — which,  moreover,  are  often  divided  into 
two  or  more  classes,  corresponding  with  the  different 
"  castes."  Yet  the  neuters,  being  barren  females, 
never  have  an  opportunity  of  bequeathing  their 
instincts  to  progeny.  Thus  it  appears  necessary  to 
*  See  Mental  Evolution  in  Animals,  pp.  377-8. 


lii 


i 


lies, 
leir 
to 


Characters,  Hereditary  and  Acquired.    93 

suppose  that  the  instincts  of  all  the  different  castes  of 
neuters  are  latent  in  the  queen  and  drones,  together 
v;ith  the  other  instincts  which  are  patent  in  both. 
Lastly,  it  seems  necessary  to  suppose  that  all  this 
wonderful  organization  of  complex  and  segregated 
instincts  must  have  been  built  up  by  natural  selection 
acting  exclusively  on  the  queens  and  drones — seeing 
that  these  exercise  their  own  instincts  only  once  in 
a  life-time,  while,  as  just  observed,  the  neuters  cannot 
possibly  bequeath  their  individual  experience  to 
progeny.  Obviously,  however,  natural  selection  must 
here  be  supposed  to  be  operating  at  an  immense 
disadvantage ;  for  it  must  have  built  up  the  often 
diverse  and  always  complex  instincts  of  neuters,  not 
directly,  but  indirectly  through  the  queens  and  drones, 
which  never  manifest  any  of  these  instincts  themselves. 
Now  Darwin  fully  acknowledged  the  difficulty  of 
attributing  these  results  to  the  unaided  influence  of 
natural  selection ;  but  the  fact  of  neuter  insects  being 
unable  to  propagate  seemed  to  him  to  leave  no 
alternative.  And  so  it  seems  to  Weismann,  who 
accordingly  quotes  these  instincts  in  support  of  his 
views.  And  so  it  seemed  to  me,  until  my  work 
on  Animal  Intelligence  was  translated  into  French, 
and  an  able  Preface  was  supplied  to  that  translation 
by  M.  Perrier.  In  this  Preface  it  is  argued  that  we 
are  not  necessarily  obliged  to  exclude  the  possibility 
of  Lamarckian  principles  having  operated  in  the 
original  formation  of  these  instincts.  On  the  contrary, 
if  such  principles  ever  operate  at  all,  Perrier  shows 
that  here  we  have  a  case  where  it  is  virtually  certain 
that  they  must  have  operated.  For  although  neuter 
insects  are  now  unable  to  propagate,  their  organiza- 


::: 

s 


'J 

i 


•'ft 

\ 


V 

♦1 

m 
\ 

"I 

^(11 


94 


Darwin,  and  after  Darwin. 


V, 

't 

I* 


II 


if 


l|M 


1 


n 


4 

i 

(Ill 


tion  indicates — if  it  does  not  actually  prove — that 
they  are  descended  from  working  insects  which  were 
able  to  propagate.  Thus,  in  all  probability,  what  we 
now  call  a  "  hive  "  was  originally  a  society  of  sexually 
mature  insects,  all  presenting  the  same  instincts,  both 
as  to  propagation  and  to  co-operation.  When  these 
instincts,  thus  common  to  all  individuals  composing 
the  hive,  had  been  highly  perfected,  it  became  of 
advantage  in  the  struggle  for  existence  (between 
different  hives  or  communities)  that  the  functions 
of  reproduction  should  devolve  more  upon  some 
individuals,  while  those  of  co-operation  should  devolve 
more  upon  others.  Consequently,  this  division  of 
labour  began,  and  gradually  became  complete,  as 
we  nuw  find  it  in  bees  and  ants.  Perrier  sustains 
the  hypothesis  thus  briefly  sketched  by  pointing 
to  certain  species  of  social  hymenoptera  where 
we  may  actually  observe  different  stages  of  the 
process — from  cases  where  all  the  females  of  the 
hive  are  at  the  same  time  workers  and  breeders,  up 
to  the  cases  where  the  severance  between  these  func- 
tions has  become  complete.  Therefore,  it  seems  to 
me,  it  is  no  longer  necessary  to  suppose  that  in  these 
latter  cases  all  the  instincts  of  the  (now)  barren  females 
can  only  have  been  due  to  the  unaided  influence  of 
natural  selection. 

Nevertheless,  although  I  think  that  Perrier  has 
made  good  his  position  thus  far,  that  his  hypothesis 
fails  to  account  for  some  of  the  instincts  which  are 
manifested  by  neuter  insects,  such  as  those  which,  so 
far  as  I  can  see,  must  necessarily  be  supposed  to 
have  originated  after  the  breeding  and  working 
functions  had   become   separated — seeing   that  they 


Characters f  Hereditary  a7id  Acquired.    95 

appear  to  have  exclusive  reference  to  this  peculiar 
state  of  matters.  Possibly,  however,  Perricr  might 
be  able  to  meet  each  of  these  particular  instincts, 
by  showing  how  they  could  have  arisen  out  of 
simpler  beginnings,  prior  to  the  separation  of  the  two 
functions  in  question.  There  is  no  space  to  consider 
such  possibilities  in  detail  ;  but,  until  this  shall 
have  been  done,  I  do  not  think  we  are  entitled  to 
conclude  that  the  phenomena  of  instinct  as  presented 
by  neuter  insects  are  demonstrably  incompatible  with 
the  doctrines  of  Lamarck — or,  that  these  phenomena 
are  available  as  a  logical  proof  of  the  unassisted 
agency  of  natural  selection  in  the  case  of  instincts 
in  general  ^ 


(B.) 

Inherited  Effects  of  Use  and  of  Disuse, 

There  is  no  doubt  that  Darwin  everywhere  attaches 
great  weight  to  this  line  of  evidence.  Nevertheless, 
in  my  opinion,  there  is  equally  little  doubt  that, 
taken  by  itself,  it  is  of  immeasurably  less  weight  than 
Darwin  supposed.  Indeed,  I  quite  agree  with  Weis- 
mann  that  the  whole  of  this  line  of  evidence  is 
practically  worthless  ;  and  for  the  following  reasons. 

The  evidence  on   which    Darwin    relied    to    prove 

'  [See  II.  Spencer,  The  Inadequacy  of  Natural  Selection,  A  Rejoinder 
to  Professor  Weismann,  Contemp.  Kev.  1893;  and  Weismaunism  once 
w^r^,  Ibid.  Oct.  1894  ;  Weismann,  The  All-sufficiency  of  A'atural  Selection, 
Il.id.  1893;  and  The  Effect  of  External  Influences  upon  Development, 
"Romanes  Lecture"  1S94:  also  Neuter  Insects  and  Lamarckism, 
W.  Piatt  Kail,  Natural  Science,  Feb.  1894,  and  Neuter  Insects  and 
Darwinism,  J.  T.  Cunningham,  Ibid.  April  1894.     C.  LI.  M.] 


'J 


96  Darwifiy  and  after  Darwin. 


iH  c^ 


Mr 


ft 


»i 


ii 


:;-h 


the  inherited  effects  of  use  and  disuse  was  derived 
from  his  careful  measurements  of  the  increase  or 
decrease  which  certain  bones  of  our  domesticated 
animals  have  undergone,  as  compared  with  the  cor- 
responding bones  of  ancestral  stocks  in  a  state  of 
nature.  He  chose  domesticated  animals  for  these 
investigations,  because,  while  yielding  unquestionable 
cases  of  increased  oi  diminished  use  of  certain  organs 
over  a  large  number  of  sequent  generations,  the  results 
were  not  complicated  by  the  possible  interference 
of  natural  selection  on  the  one  hand,  or  by  that 
of  the  economy  of  nutrition  on  the  other.  For  "  with 
highly-fed  domesticated  animals  there  seems  to  be 
no  economy  of  growth,  or  any  tendency  to  the  elimi- 
nation of  superfluous  details^;"  seeing  that,  among 
other  considerations  pointing  in  the  same  direction, 
"  structures  which  are  rudimentary  in  the  parent 
species,  sometimes  become  partially  re-developed  in 
our  domesticated  productions^." 

The  method  of  Darwin's  researches  in  this  con- 
nexion was  as  follows.  Taking,  for  example,  the  case 
of  ducks,  he  carefully  weighed  and  measured  the 
wi.ig-bones  and  leg-bones  of  wild  and  tame  ducks; 
and  he  found  that  the  wing-bones  were  smaller, 
whili  the  leg-bones  were  larger,  in  the  tame  than  in 
the  wild  specimens.  These  facts  he  attributed  to  many 
generations  of  tame  ducks  using  their  wings  less,  and 
their  legs  more,  than  was  the  case  with  their  wild 
ancestry.  Similarly  he  compared  the  leg-bones  of 
wild  rabbits  with  those  of  tame  ones,  and  so  forth — 
in  all  cases  finding  that  where  domestication  had  led 
to  increased  use  of  a  part,  that  part  was  larger  than  in 

'  Variation  of  Plants  and  Animals^  vol.  iu  p.  389.        •  Ibid.  p.  346. 


the 

ler, 
in 


of 
h— 
led 
■a  in 


Characters^  Hereditary  and  Acquired.    97 

the  wild  parent  stock  ;  while  the  reverse  was  the  case 
with  parts  less  used.  Now,  although  at  first  sight 
these  facts  certainly  do  seem  to  yield  good  evidence 
of  the  inherited  effects  of  use  and  disuse,  they  are 
really  open  to  the  following  very  weighty  objections. 

First  of  all,  there  is  no  means  of  knowing  how 
far  the  ob..jrved  efifects  may  have  been  due  to  in- 
creased or  diminished  use  during  only  the  individual 
life-time  of  each  domesticated  animal.  Again,  and 
this  is  a  more  important  point,  in  all  Darwin's 
investigations  the  increase  or  decrease  of  a  part 
was  estimated,  not  by  directly  comparing,  say  the 
wing-bones  of  a  domesticated  duck  with  the  wing- 
bones  of  a  wild  duck,  but  by  comparing  the  ratio 
between  the  wing  and  leg  bones  of  a  tame  duck 
with  the  ratio  between  the  wing  and  leg  bones 
of  a  wild  duck.  Consequently,  if  there  be  any  reason 
to  doubt  the  supposition  that  a  really  inherited 
decrease  in  the  size  of  a  part  thus  estimated  is  due 
to  the  inherited  effects  of  disuse,  such  a  doubt  will 
also  extend  to  the  evidence  of  increased  size  being 
due  to  the  inherited  effects  of  use.  Now  there  is  the 
gravest  possible  doubt  lyin^  against  the  supposition 
that  any  really  inherited  decrease  in  the  size  of  a 
part  is  due  to  the  inherited  effects  of  disuse.  For 
it  may  be — and,  at  any  rate  to  some  extent,  must 
be — due  to  another  principle,  which  it  is  strange  that 
Darwin  should  have  overlooked.  This  is  tne  prin- 
ciple which  Weismann  has  called  Panmixia,  and  which 
cannot  be  better  expressed  than  in  his  own  words  : — 

"  A  goose  or  a  duck  must  possess  strong  powers  of  flight  in  the 
natural  state,  but  such  powers  are  no  longer  necessary  for 
obtaining  food  when  it  is  brought  into  the  poukry-yard;    so 

II.  H 


i.  m 


s 
^1 


r  11 


'»!. 


(I  4 


98  Darwifif  and  after  Darwin, 

that  a  rigid  selection  of  individuals  with  well-developed  wings 
at  once  ceases  among  its  descendants.  Hence,  in  the  course 
of  generations,  a  deterioration  of  the  organs  of  flight  must 
necessarily  ensue  *." 

Or,  to  state  the  case  in  atiother  way:  if  any 
structure  which  was  originally  built  up  by  natural 
selection  on  account  of  its  use,  ceases  any  longer 
to  be  of  so  much  use,  in  whatever  degree  it  ceases 
to  be  of  use,  in  that  degree  will  the  premium  before 
set  upon  it  by  natural  selection  be  withdrawn.  And 
the  consequence  of  this  withdrawal  of  selection  as 
regards  that  particular  part  will  be  to  allow  the 
part  to  degenerate  in  successive  generations.  Such 
is  the  principle  which  Weismann  calls  Panmixia, 
because,  by  the  withdrawal  of  selection  from  any 
particular  part,  promiscuous  breeding  ensues  with 
regard  to  that  part.  And  it  is  easy  to  see  that 
this  principle  must  be  one  of  very  great  importance 
in  nature ;  because  it  must  necessarily  come  into 
operation  in  all  cases  where  any  structure  or  any 
instinct  has,  through  any  change  in  the  environment 
or  in  the  habits  of  a  species,  ceased  to  be  useful. 
It  is  likewise  easy  to  see  that  its  effect  must  be 
the  same  as  that  which  was  attributed  by  Darwin 
to  the  inherited  effect  of  disuse ;  and,  therefore,  that 
the  evidence  on  which  he  relied  in  proof  of  the 
inherited  effects  both  of  use  and  of  disuse  is  vitiated 
by  the  fact  that  the  idea  of  Panmixia  did  not  occur  to 
him. 

Here,  however,  it  may  be  said  that  the  idea  first 
occurred   to   me^   just   after  the   publication  of  the 

*  Essays,  i.  p.  90. 

•  Nature,  vol.  ix.  pp.  361-a,  440-1 ;  and  vol.  x.  p.  164. 


I   I    I 


Characters,  Hereditary  and  Acquired.    99 

last  edition  Oi"  the  Origin  of  Species.  I  called  the 
principle  the  Cessation  of  Selection— which  I  still 
think  a  better,  because  a  more  descriptive,  term 
than  Panmixia  ;  and  at  that  time  it  appeared  to  me, 
as  it  now  appears  to  Wcismann,  entirely  to  supersede 
the  necessity  of  supposing  that  the  effect  of  disuse  is 
ever  inherited  in  any  degree  at  all.  Thus  it  raised 
th*  whole  question  as  to  the  admissibility  of  La- 
marckian  principles  in  general ;  or  the  question  on 
which  we  are  now  engaged  touching  the  possible 
inheritance  of  acquired,  as  distinguished  from  con- 
genital, characters.  But  on  discussing  the  matter 
with  Mr.  Darwin,  he  satisfied  me  that  the  larger 
question  was  not  to  be  so  easily  closed.  That  is  to 
say,  although  he  fully  accepted  the  principle  of  the 
Cessation  of  Selection,  and  as  fully  acknowledged 
its  obvious  importance,  he  convinced  me  that  tliere 
was  independent  evidence  for  the  transmission  of 
acquired  characters,  sufficient  in  amount  to  leave 
the  general  structure  of  his  previous  theory  unaffected 
by  what  he  nevertheless  recognized  as  a  factor  which 
must  necessarily  be  added.  All  this  I  now  mention 
in  order  to  show  that  the  issue  which  Weismann 
has  raised  since  Darwin's  death  was  expressly  con- 
templated during  the  later  years  of  Darwin's  life. 
For  if  the  idea  of  Panmixia — in  the  absence  of  which 
Weismann's  entire  system  would  be  impossible — 
had  never  been  present  to  Darwin's  mind,  we  should 
have  been  left  in  uncertainty  how  he  would  have 
regarded  this  subsequent  revolt  against  what  are 
generally  called  the  Lamarckian  principles  ^ 

Moreover,  in   this   connexion  we  must   take  par- 

^  Appendix  I. 
H   2 


I: 


S 


5 


*• 
^ 


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ticular  notice  that  the  year  after  I  had  pubh'shed 
these  articles  on  the  Cessation  of  Selection,  and 
discussed  with  Mr.  Darwin  the  liearing  of  this  prin- 
ciple on  the  question  of  the  transmission  of  acquired 
characters,  Mr.  Galton  followed  with  his  hij^hly 
important  essay  on  Heredity.  For  in  this  essay 
Mr.  Galton  fully  adopted  the  principle  of  the  Cessa- 
tion of  Selection,  and  was  in  consequence  the  first 
publicly  to  challenge  the  Laniarckian  principles — 
pointing  out  that,  if  it  were  thus  possible  to  deny 
the  transmission  of  acquired  characters  in  toto^  "we 
should  be  relieved  from  all  further  trouble";  but 
that,  if  such  characters  are  transmitted  '•  in  however 
faint  a  degree,  a  complete  theory  of  heredity  must 
accoun*  for  them."  Thus  the  question  which,  in  its 
revived  condition,  is  now  attracting  so  much  attention, 
was  propounded  in  all  its  parts  some  fifteen  or  six- 
teen years  ago;  and  no  additional  facts  or  new 
considerations  of  any  great  importance  bearing  upon 
the  subject  have  been  adduced  since  that  time.  In 
other  words,  about  a  year  after  my  own  conversations 
with  Mr.  Darwin,  the  whole  matter  was  still  more 
effectively  brought  before  his  notice  by  his  own 
cousin.  And  the  result  was  that  he  still  retained  his 
belief  in  the  Lamarckian  factors  of  organic  evolution, 
even  more  strongly  than  it  was  retained  either  by 
Mr.  Galton  or  myself*. 

We  have  now  considered  the  line  of  evidence  on 
which  Darwin  chiefly  relied  in  proof  of  the  transmis- 
sibility  of  acquired  characters ;  and  it  must  be  allowed 
that  this   line  of  evidence    is  practically   worthless. 

*  For  a  fuller  statement  of  Mr.  Galton's  theory  of  Heredity,  and  iti 
relation  to  Weismann's,  see  An  Examination  of  Weismannism. 


by 


Characters f  Hereditary  and  Acquired.   loi 

Wliat  he  regarded  as  the  inherited  tfTccts  of  use  and 
of  disuse  may  be  cniiicly  due  to  the  cessation  of 
selection  in  the  case  of  our  domesticated  animals, 
combined  with  an  active  reversal  of  selection  in  the 
case  of  natural  species.  And  m  accordance  with 
this  view  is  the  fact  that  the  degeneration  of  disused 
parts  proceeds  much  further  in  the  case  of  wild 
species  than  it  does  in  that  of  domesticated  varieties. 
For  although  it  may  be  said  that  in  the  case  of  wild 
species  more  time  has  been  allowed  for  a  greater 
accumulation  of  the  inherited  effects  of  disuse  than 
can  have  been  the  case  with  domesticated  varieties, 
the  alternative  explanation  is  at  least  as  probable — 
that  in  the  case  of  wild  species  the  merely  negative, 
or  passive,  influence  of  the  cessation  of  selection  has 
been  continuously  and  powerfully  assisted  by  the 
positive,  or  active,  influence  of  the  reversal  o^  selection, 
through  economy  of  growth  and  the  general  advantage 
to  be  derived  from  the  abolition  of  useless  parts  *. 

The  absence  of  any  good  evidence  of  this  direct 
kind  in  favour  of  use-inheritance  will  be  rendered 
strikingly  apparent  to  any  cme  who  reads  a  learned 
and  interesting  work  by  Professor  Semper  **.  His 
object  was  to  show  the  large  part  which  he  believed 
to  have  been  played  by  external  conditions  of  life  in 
directly  modifying  organic  types — or.  in  other  words, 
of  proving  that  side  of  Lamarckianism  which  refers 
to  the  immediate  action  of  the  environment;  whether 
with  or  without  the  co-operation  of  use-inheritance 
and    natural    selection.    Although  Semper  gathered 

*  For  a  fuller  explanation  of  the  importan*-  difference  between  the 
mere  cessation  and  the  actnal  reversal  of  selection,  see  Appendix  I. 
'  Animal  Life,  International  Scientific  Series,  vol.  xxxi. 


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I02        Darwin^  and  after  Darwin, 

together  a  great  array  of  facts,  the  more  carefully 
one  reads  his  book  the  more  apparent  does  it  become 
that  no  single  one  of  the  facts  is  in  itself  conclusive 
evidence  of  the  transmission  to  p  ogeny  of  char- 
acters which  are  acquired  through  uswvinheritance  or 
through  direct  action  of  the  environment.  Every  one 
of  the  facts  is  susceptible  of  explanation  on  the 
hypothesis  that  the  principle  of  natural  selection 
has  been  the  only  principle  concerned.  This,  how- 
ever, it  must  be  observed,  is  by  no  means  equivalent 
to  proving  that  characters  thus  acquired  are  not 
transmitted.  As  already  pointed  out,  it  is  imprac- 
ticable with  species  in  a  state  of  nature  to  disso- 
ciate the  distinctively  Darwinian  from  the  possibly 
Lamarcki£.n  factors;  so  that  even  if  the  latter 
are  largely  operative,  we  can  only  hope  for  direct 
evidence  of  the  fact  from  direct  experiments  on 
varieties  in  a  state  of  domestication.  To  this  branch 
of  our  subject,  therefore,  we  will  now  proceed. 


'¥, 


^^ 


II 


CHAPTER  IV. 

Characters  as  Hereditary  and  Acquired 

(contitmed). 

(C.) 

Experimental  Evidence  in  favour  of  the  Inheritance 
of  Acquired  Characters. 

Notwithstanding  the  fact  already  noticed,  that 
no  experiments  have  hitherto  been  published  with 
reference  to  the  question  of  the  transmission  of 
acquired    characters  \    there    are    several    researches 

*  The  experiments  of  Galton  and  Weismann  upon  this  subject  are 
nugatory,  as  will  be  shown  later  on.  But  since  the  above  was  written 
an  important  research  has  been  published  by  Mr.  Cunningham,  of  the 
Marine  Biological  Association.  For  a  full  account  I  must  refer  the 
reader  to  his  forthcoming  paper  in  the  Philosophical  Transactions.  The 
following  is  his  own  statement  of  the  principal  results : — 

"A  case  which  I  have  myself  recently  investigated  experimentally 
seems  to  me  to  support  very  strongly  the  theory  of  the  inheritance  of 
acquired  characters.  I  have  shown  that  in  normal  flat-fishes,  if  the 
lower  side  be  artificially  exposed  to  light  for  a  long  time,  pigmen- 
tation is  developed  on  that  side ;  but  when  the  exposure  is  commenced 
while  the  specimens  are  still  in  process  of  metamorphosis,  when 
pigment-cells  are  still  present  on  the  lower  side,  the  action  of  light 
does  not  prevent  the  disappearance  of  these  pigment-cells.  They 
disappear  as  in  individuals  living  under  normal  conditions,  but  after 
prolonged  exposure  pigment-cells  reappear.  The  first  fact  proves  that 
the  disappearance  of  the  pigment-cells  from  the  lower  side  in  the 
metamorphosis  is  an  hereditary  character,  and  not  a  change  produced  in 
each  individual  by  the  withdrawal  of  the  lower  side  from  the  action 
of  light    On  the  other  hand,  the  experiments  show  that  the  absence  of 


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104         Darwin,  and  after  Darwin. 

which,  with  other  objects  in  view,  have  incidentally 
yielded  seemingly  good  evidence  of  such  transmission. 
The  best-known  of  these  researches — and  therefore 
the  one  with  which  I  shall  begin — is  that  of  Brown- 
Sdquard  touching  the  effects  of  certain  injuries  of  the 
nervous  system  in  guinea-pigs. 

During  a  period  of  thirty  years  Brown-Sdquard 
bred  many  thousands  of  guinea-pigs  as  material  fur 
his  various  researches ;  and  in  those  whose  parents 
had  not  been  operated  upon  in  the  ways  to  be 
immediately  mentioned,  he  never  saw  any  of  the 
peculiarities  which  are  about  to  be  described  There- 
fore the  hypothesis  of  coincidence,  at  all  events,  must 
be  excluded.  The  following  is  his  own  summary 
of  the  results  with  which  we  are  concerned : — 

1st.  Appearance  of  epilepsy  in  animals  born  of  parents  which 
had  been  rendered  epileptic  by  an  injury  to  the  spinal  coid. 

2nd.  Appearance  of  epilepsy  also  in  animals  bom  of  parents 
which  had  been  rendered  epileptic  by  section  of  the  sciatic  nei-ve. 

3rd.  A  change  in  the  shape  of  the  ear  in  animals  born  of 
parents  in  which  such  a  change  was  the  effect  of  a  division 
of  the  cervical  sympathetic  nerve. 

4th.  Partial  closure  of  the  eyelids  in  animals  bom  of  parents 

pigment-cells  from  the  lower  side  throughout  life  is  due  ^o  the  fact 
that  light  does  not  act  apon  that  side,  for,  when  it  is  allowed  to 
act,  pigment-cells  appear.  It  seems  to  me  the  only  reasonable  con- 
clusion from  these  facts  is,  that  the  disappearance  of  pigment-cells  was 
originally  due  to  the  absence  of  light,  and  that  this  change  has  now 
become  hereditary.  The  pigment-cells  produced  by  the  action  of  light 
on  the  lower  side  are  in  all  respects  similar  to  those  normally  present 
on  the  upper  side  of  the  fish.  If  the  disappearance  of  the  pigment-cells 
were  due  entirely  to  a  variation  of  the  germ-plasm,  no  external  influence 
could  cause  them  to  reappear,  and,  on  the  other  hand,  if  there  were  no 
hereditary  tendency,  the  colouration  of  the  lower  side  of  the  flat-fish 
when  exposed  would  be  rapid  and  complete." — Natural  Science^ 
Oct.  1893. 


Characters,  Hereditary  and  Acquired.  105 


in  which  that  state  of  the  eyelids  had  been  caused  either  by 
section  of  the  cervical  sympathetic  nerve,  or  the  removal  of  the 
superior  cervical  ganglion. 

5th.  Exophthalmia  in  animals  bom  of  parents  in  which  an 
injury  to  the  restiform  body  had  produced  that  protrusion  of  the 
eyeball.  This  interesting  fact  I  have  witnessed  a  good  many 
times,  and  seen  the  transmission  of  the  morbid  state  of  the 
eye  continue  through  four  generations.  In  these  animals, 
modified  by  heredity,  the  two  eyes  generally  protruded,  although 
in  the  parents  usually  only  one  showed  exophthalmia,  the  lesion 
having  been  made  in  most  cases  only  on  one  of  the  corpora 
restiformia. 

6th.  Haematoma  and  dry  gangrene  of  the  ears  in  animals 
born  of  parents  in  which  these  ear-alterations  had  been  caused 
by  an  injury  to  the  restiform  body  near  the  nib  of  the  calamus. 

7th.  Absence  of  two  toes  out  of  the  three  of  the  hind  leg,  and 
sometimes  of  the  three,  in  animals  whose  parents  had  eaten  up 
their  hind-leg  toes  which  had  become  anaesthetic  from  a  section 
of  the  sciatic  nerve  alone,  or  of  that  nerve  and  also  of  the  crural. 
Sometimes,  instead  of  complete  absence  of  the  toes,  only  a  part 
of  one  or  two  or  three  was  missing  in  the  young,  although  in  the 
parent  not  only  the  toes  but  the  whole  foot  were  absent  (partly 
eaten  off,  partly  destroyed  by  inflammation,  ulceration,  or 
gangrene.) 

8th.  Appearance  of  various  morbid  states  of  the  skin  and 
hair  of  the  neck  and  face  in  animals  born  of  parents  having  had 
similar  alterations  in  the  same  parts,  as  effects  of  an  injury  to 
the  sciatic  nerve. 


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These  results  ^  have  been  independently  vouched 
for  by  two  of  Biown-S^quard's  former  assistants — 
Dr.  Dupuy,  and  the  late  Professor  Westphal. 
Moreover,  his  results  with  regard  to  epilepsy  have 
been    corroborated    also    by   Obersteiner^.      I    may 

^  For  Professor  Weismaim's  statement  of  and  discussion  of  these 
results  see  Essays,  vol.  i.  p.  313. 

"  Oesterrfichische  medicinische  Jahrhucher.  1875,  179. 


■•^■MaMi^MB 


!     I 


io6         Darwin^  and  after  Darwin, 

observe,  in  passing,  that  this  labour  of  testing  Brown- 
S^quard's  statements  is  one  which,  in  my  opinion, 
ought  rather  to  have  been  undertalcen,  if  not  by 
Weismann  himself,  at  all  events  by  some  of  his 
followers.  Both  he  and  they  are  incessant  in  their 
demand  for  evidence  of  the  transmission  of  acquired 
characters ;  yet  they  have  virtually  ignored  the  fore- 
going very  remarkable  statements  However,  be 
this  as  it  may,  all  that  we  have  now  to  do  is  to 
consider  what  the  school  of  Weismann  has  had  to  say 
with  regard  to  these  experiments  on  the  grounds  of 
general  reasoning  which  they  have  thus  far  been 
satisfied  to  occupy. 

In  view  of  Obersteiner's  corroboration  of  Brown- 
Sequard  s  results  touching  the  artificial  production 
and  subsequent  transmission  of  epilepsy,  Weismann 
accepts  the  facts,  but,  in  order  to  save  his  theory 
of  heredity,  he  argues  that  the  transmission  may 
be  due  to  a  traumatic  introduction  of  "  some  unknown 
microbe"  which  causes  the  epilep'^y  in  the  parent, 
and,  by  invading  the  ova  or  spermatozoa  as  the 
case  may  be,  also  produces  epilepsy  in  the  offspring. 
Here,  of  course,  there  would  be  transmission  of 
epilepsy,  but  it  would  not  be,  technically  speaking, 
an  hereditary  transmission.  The  case  would  resemble 
that  of  syphilis,  where  the  sexual  elemmts  remain 
unaffected  as  to  their  congenital  endowments,  although 
they  have  been  made  the  vehicles  for  conveying  an 
organic  poison  to  the  next  generation. 

Now  it  would  seem  that  this  suggestion  is  not, 
on  the  face  of  it,  a  probable  one.  For  "some  un- 
known microbe"  it  indeed  must  be,  which  is  always 
on  hand  to  enter  a  guinea-pig  when  certain  operations 


Characters  J  Hereditary  and  Acquired.  107 

are  being  performed  on  certain  parts  of  the  nervous 
system,  but  yet  will  never  enter  when  operations 
of  any  kind  are  being  effected  elsewhere.  Moreover, 
Westphal  has  produced  the  epilepsy  without  any 
incision^  by  striking  the  heads  of  the  animals  with 
a  hammer  ^  This  latter  fact,  it  appears  to  me, 
entirely  abolishes  the  intrinsically  improbable  sugges- 
tion touching  an  unknown — and  strangely  eclectic — 
microbe.  However,  it  is  but  fair  to  state  what 
Weismann  himself  has  made  of  this  fact.  The  fol- 
lowing is  what  he  says : — 

"  It  is  obvious  that  the  presence  of  microbes  can  have  nothing 
to  do  with  such  an  attack,  but  the  shock  alone  must  have  caused 
morphological  and  functional  changes  in  the  centre  of  the  pons 
and  medulla  oblongata,  identical  with  those  produced  by  microbes 
in  the  other  cases.  .  .  .  Various  stimuli  might  cause  the  nervous 
centres  concerned  to  develop  the  convulsive  attack  which, 
together  with  its  after-effects,  we  call  epilepsy.  In  Westphal's 
case,  such  a  stimulus  would  be  given  by  a  powerful  mechanical 
shock  (viz.  blows  on  the  head  with  a  hammer) ;  in  Brown- 
Sdquard's  experiments,  by  the  penetration  of  microbes  '." 

But  from  this  passage  it  would  seem  that  Weismann 
has  failed  to  notice  that  in  *'  Westphal's  case,"  as 
in  "  Brown-S^quard's  experiments,"  the  epilepsy  was 
transmitted  to  progeny.  That  epilepsy  may  be  pro- 
duced in  guinea-pigs  by  a  method  which  does  not 
involve  any  cutting  (i.e.  possibility  of  inoculation) 
would  no  doubt  tend  to  corroborate  the  suggestion 
of  microbes  being  concerned  in  its  transmission  when 
it  is  produced  by  cutting,  if  in  the  former  case  there 
were  no  such  transmission.  But  as  there  is  trans- 
mission in  both  cases,  the  facts,  so  far  as  I  can  see, 


it 


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io8        Darwin,  and  after  Darwin, 

entirely  abolish  the  suggestion.  For  they  prove  that 
even  when  epilepsy  is  produced  in  the  parents  under 
circumstances  which  render  "it  obvious  that  the 
presence  of  microbes  can  have  nothing  to  do  with 
such  an  attack,"  the  epileptiform  condition  is  not- 
withstanding transmitted  to  the  progeny.  What, 
then,  is  gained  by  retaining  the  intrinsically  im- 
probable hypothesis  of  microbes  to  explain  the  fact 
of  transmission  "  in  Brown-Scquard's  experiments," 
when  this  very  same  fact  is  proved  to  occur  without 
the  possibility  of  microbes  "  in  Westphars  case  "  ? 

The  only  other  objection  with  regard  to  the  seeming 
transmission  of  traumatic  epilepsy  which  Weismann 
has  advanced  is,  th^t  such  epilepsy  may  be  produced 
by  two  or  three  very  different  operations — viz.  division 
of  the  sciatic  nerves  (one  or  both),  an  injury  to  the 
spinal  cord,  and  a  stroke  on  the  head.  Does  not 
this  show,  it  is  asked,  that  the  epileptic  condition 
of  guinea-pigs  is  due  to  a  generally  unstable  condition 
of  the  whole  nervous  system,  and  is  not  associated 
with  any  particular  part  thereof?  Well,  supposing 
that  such  is  the  case,  what  would  it  amount  to? 
I  cannot  see  that  it  would  in  any  way  affect  the 
only  question  in  debate — viz.  What  is  the  significance 
of  the  fact  that  epilepsy  is  irattsmitted}  Even  if  it 
be  but  "  a  tendency,"  *"  a  disposition,"  or  "  a  diathesis  '* 
that  is  transmitted,  it  is  none  the  less  a  case  of 
transmission,  in  fact  quite  as  much  so  as  if  the  patho- 
logical state  were  dependent  on  the  impaired  condition 
of  any  particular  nerve-centre.  For,  it  must  be 
observed;  there  can  be  no  question  that  it  is  always 
produced  by  an  operation  of  some  kind.  If  it  were 
ever  to  originate  in  guinea-pigs  spontaneously,  there 


Characters^  Hereditary  and  Acquired.  109 


»i 


might  be  some  room  for  supposing  that  its  trans- 
mission is  due  to  a  congenital  tendency  running 
through  the  whole  species — although  even  then  it 
would  remain  unaccountable,  on  the  ultra-Darwinian 
view,  why  this  tendency  should  be  congenitally 
increased  by  means  of  an  operation.  But  epilepsy 
does  not  originate  spontaneously  in  guinea-pigs ; 
and  therefore  the  criticism  in  question  appears  to  me 
irrelevant. 

Again,  it  may  be  worth  while  to  remark  that 
Brown-S^quard's  experiments  do  not  disprove  the 
possibility  of  its  being  some  one  nerve-centre  which 
is  concerned  in  all  cases  of  traumatic  epilepsy.  And 
this  possibility  becomes,  I  think,  a  probability  in  view 
of  Luciani's  recent  experiments  on  the  dog.  These 
show  that  the  epileptic  condition  can  be  produced 
in  this  animal  by  injury  to  the  cortical  substance 
of  the  hemispheres,  and  is  then  transmitted  to  pro- 
geny'. These  experiments,  therefore,  are  of  great 
interest — first,  as  showing  that  traumatic  and  trans- 
missible epilepsy  is  not  confined  to  guinea-pigs ; 
and  next,  as  indicating  that  the  pathological  state 
in  question  is  associated  with  the  highest  nerve- 
centres,  which  may  therefore  well  be  affected  by 
injury  to  the  lower  centres,  or  even  by  section  of  a 
large  neive  trunk. 

So  much,  then,  with  regard  to  the  case  of  trans- 
mitted epilepsy.  But  now  it  must  be  noted  that, 
even  if  Weismann's  suggestion  touching  microbes 
were  fully  adequate  to  meet  this  case,  it  would  still 
leave  unaffected  those  of  transmitted  protrusion  of 
the  eye,  drooping  of  the  eyelid,  gangrene  of  the 
'  Lesfonctions  du  Ctrveau,  p.  loa. 


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ear,  absence  of  toes,  &c.  In  all  these  cases  the  facts, 
as  stated  by  Brown-S^quard,  are  plainly  unamenable 
to  any  explanation  which  would  suppose  them  due 
to  microbes,  or  even  to  any  general  neurotic  con- 
dition induced  by  the  operation.  They  are  much  too 
definite,  peculiar,  and  localized.  Doubtless  it  is  on 
this  account  that  the  school  of  Weismann  has  not 
seriously  attempted  to  deal  with  them,  but  merely 
recommends  their  repetition  by  other  physiologists  *. 
Certain  criticisms,  however,  have  been  urged  by 
Weismann  against  the  interpretation  of  Brown- 
S^quard's  facts  as  evidence  in  favour  of  the  trans- 
mission of  acquired  characters.  It  does  not  appear 
to  me  that  these  criticisms  present  much  weight ; 
but  it  is  only  fair  that  we  should  here  briefly  consider 
them  ^. 

First,  with  regard  to  Brown- S^quard's  results  other 
than  the  production  of  transmitted  epilepsy,  Weismann 
allows  that  the  hypothesis  of  microbes  can  scarcely 
apply.  In  order  to  meet  these  results,  therefore,  he 
furnishes  another  suggestion — viz.  that  where  the 
nervous  system  has  sustained  "  a  great  shock, "  the 
animals  are  very  likely  to  bear  "  weak  descendants, 
and  such  as  are  readily  affected  by  disease."  Then,  in 
answer  to  the  obvious  consideration,  "that  this  does 
not  explain  why  the  offspring  should  suffer  from  the 
same  disease "  as  that  which  has  been  produced 
in  the  parents,  he  adds — '  But  this  does  not  appear 
to  have  been   by  any   means    invariably   the   case. 

*  Essays,  vol.  i.  p.  Sa. 

'  As  Weismann  gives  an  excellent  abstract  of  all  the  alleged  facts  up 
to  date  {Essays,  vol"  i.  pp.  319-324),  it  is  needless  for  me  to  supply 
another,  further  than  that  which  I  have  already  made  from  Brown- 
S^quard. 


I 

'  k 


Characters f  Hereditary  and  Acquired,  iii 

For  '  Brown-S^quard  himself  says,  the  changes  in 
the  eye  of  the  offspring  were  of  a  very  variable 
nature,  and  were  only  occasionally  exactly  similar 
to  those  observed  in  the  parents.'  " 

Now,  this  does  not  appear  to  me  a  good  com- 
mentary. In  the  first  place,  it  docs  not  apply  to 
the  other  cases  (such  as  the  ears  and  the  toes), 
where  the  changes  in  the  offspring,  when  they 
occurred  at  all,  were  exactly  similar  to  those  observed 
in  the  parents,  save  that  some  of  them  occasionally 
occurred  on  the  opposite  side,  and  frequently  also  on 
both  sides  of  the  offspring.  These  subordinate  facts, 
however,  will  not  be  regarded  by  any  physiologist 
as  making  against  the  more  ready  interpretation  of 
the  results  as  due  to  heredity.  For  a  physiologist  well 
knows  that  homologous  parts  are  apt  to  exhibit 
correlated  variability — and  this  especially  where  varia- 
tions of  a  congenital  kind  are  concerned,  and  also 
wher^  there  is  any  reason  to  suppose  that  the  nervous 
system  is  involved.  Moreover,  even  in  the  case  of 
the  eye,  it  was  always  protrusion  that  was  caused  in 
the  parent  and  transmitted  to  the  offspring  as  a  result 
of  injuring  the  restiform  bodies  of  the  former ;  while 
it  was  always  partial  closure  of  the  eyelids  that  was 
caused  and  transmitted  by  section  of  the  sympathetic 
nerve,  or  removal  of  the  cervical  ganglia.  Therefore,  if 
we  call  such  effects  "  diseases,"  surely  it  was  *'  the  same 
disease  "  which  in  each  case  appeared  in  the  parents 
and  reappeared  in  their  offspring.  Again,  the  "  dis- 
eases "  were  so  peculiar,  definite,  and  localized,  that 
I  cannot  see  how  they  can  be  reasonably  ascribed 
to  a  general  nervous  "  shock."  Why,  for  instance, 
if  this  were  the  case,  should  a  protruding  eye  never 


»4 


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1] 


11 


1 


112         Darwin,  and  after  Darwin. 


I 
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I. 

I 

h 


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»'i-^ 


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♦n   '« 1,'; 


fl  *• 


♦I; 


result  from  removal  of  the  cervical  ganglia,  a  droop- 
ing eyelid  from  a  puncture  of  the  restiform  body, 
a  tocless  foot  from  either  or  both  of  these  opera- 
tions, and  so  on  ?  In  view  of  such  considerations  I 
cannot  deem  these  suggestions  touching  "  microbes  " 
and  "  diseases "  as  worthy  of  the  distinguished 
biologist  from  whom  they  emanate. 

Secondly,  Weismann  asks — How  can  we  suppose 
these  results  to  be  instances  of  the  transmission  of 
acquired  characters,  when  from  Brown-Sequard's  own 
statement  of  them  it  appears  that  the  mutilation 
itself  was  not  inherited,  but  only  its  effects?  Neither 
in  the  case  of  the  sciatic  nerve,  the  sympathetic  nerve, 
the  cervical  ganglion,  nor  the  restiform  bodies,  was 
there  ever  any  trace  of  transmitted  injury  in  the 
corresponding  parts  of  the  offspring ;  so  that,  if  the 
"diseases"  from  which  they  suffered  be  regarded  as 
hereditary,  we  have  to  suppose  that  a  consequence 
was  in  each  case  transmitted  without  the  transmis- 
sion of  its  cause,  which  is  absurd.  But  I  do  not  think 
that  this  criticism  can  be  deem  ;d  of  much  weight 
by  a  physiologist  as  distinguished  from  a  naturalist. 
For  nothing  is  more  certain  to  a  student  of  physiology, 
in  any  of  its  branches,  than  that  negative  evidence,  if 
yielded  by  the  microscope  alone,  is  most  precarious. 
Therefore  it  does  not  need  a  visible  change  in  the 
nervous  system  to  be  present,  in  order  that  the  part 
affected  should  be  functionally  weak  or  incapable : 
pathology  can  show  numberless  cases  of  nerve- 
disorder  the  "  structural '"  causes  of  which  neither 
the  scalpel  nor  the  microscope  can  detect.  So  that, 
if  any  peculiar  form  of  nerve-disorder  is  transmitted 
to  progeny,  and   if  it  be  certain   that  it   has  been 


Characters,  Hereditary  and  Acquired.  113 


caused  by  injury  to  some  particular  part  of  the 
nervous  system,  I  cannot  sec  that  there  is  any 
reason  to  doubt  the  tninsniission  of  a  nervous  lesion 
merely  on  the  ground  that  it  is  not  visibly  discernible. 
Of  course  there  may  be  other  grounds  for  doubting 
it ;  but  I  am  satisfied  that  this  ground  is  untenable. 
Besides,  it  must  be  remembered,  as  regards  the 
particular  cases  in  question,  that  no  one  has  thus  far 
investigated  the  histology  of  the  matter  by  the  greatly 
improved  methods  which  are  now  at  our  disposaL 

I  have  now  considered  all  the  criticisms  which 
have  been  advanced  against  what  may  be  called 
the  Lamarckian  interpretation  of  Brown-Sequard's 
results  ;  and  I  think  it  will  be  seen  that  they  present 
very  little  force — even  if  it  can  be  seen  that  they 
present  any  force  at  all.  But  it  mi  it  be  remembered 
that  this  is  a  different  thing  from  saying  that  the 
Lamarckian  interpretation  is  the  true  one.  The 
facts  alleged  are,  without  question,  highly  peculiar ; 
and,  on  this  account  alone,  Brown-Sequard's  inter- 
pretation of  them  ought  to  be  deemed  provisional. 
Hence,  although  as  yet  they  have  not  encountered 
any  valid  criticism  from  the  side  of  ultra-Darwinian 
theory,  I  do  not  agree  with  Darwin  that,  on  the  sup- 
position of  their  truth  as  facts,  they  furnish  positive 
proof  of  the  transmission  of  acquired  characters. 
Rather  do  I  agree  with  Weismann  that  further  in- 
vestigation is  needed  in  order  to  establish  such  an 
important  conclusion  on  the  basis  of  so  unusual  a 
class  of  facts.  This  further  investigation,  therefore, 
I  have  undertaken,  and  will  now  state  the  results. 

Although  this  work  was  begun  over  twenty  years 

II.  I 


^1 

h 
'^  J' 


114         Darwin,  and  after  Darwin, 


I' 


■'■•  * 
"'1 


't- 

,1, 

'fi' 


fa 

IT* 


ago,  and  then  yielded  negative  results,  it  was  only 
within  the  last  decade  that  I  resumed  it  more  system- 
atically, and  under  the  tutelage  of  Brown-S^quard 
himself.  During  the  last  two  years,  however,  the 
experiments  have  been  so  much  interrupted  by  ill- 
ness that  even  now  the  research  is  far  from  complete. 
Therefore  I  will  here  confine  myself  to  a  tabular 
statement  of  the  results  as  far  as  they  have  hitherto 
gone,  on  the  understanding  that,  in  so  far  as  they 
are  negative  or  doubtful,  I  am  not  yet  prepared  to 
announce  them  as  final. 

We  may  take  Brown-Sdquard's  propositions  in  his 
own  order,  as  already  given  on  page  104. 

I  St.  Appearance  of  epilepsy  in  animals  born  of  parents  which 
had  been  rendered  epileptic  by  an  injury  to  the  spinal  cord. 

and.  Appearance  of  epilepsy  also  in  animals  bom  of  parents 
which  had  been  rendered  epileptic  by  section  of  the  sciatic  nerve. 

I  did  not  repeat  these  experiments  with  a  view 
to  producing  epilepsy,  because,  as  above  stated,  they 
had  been  already  and  flficiently  corroborated  in 
this  respect.  But  I  repeated  many  times  the  experi- 
ments of  dividing  the  sciatic  nerve  for  the  purpose  of 
testing  the  statements  made  later  on  in  paragraphs 
7  and  8,  and  observed  that  it  almost  always  had 
the  effect  of  producing  epilepsy  in  the  animal  thus 
operated  upon — and  this  of  a  peculiar  kind,  the  chief 
characteristics  of  which  may  here  be  summarized. 
The  epileptiform  habit  does  not  supervene  until 
some  considerable  time  after  the  operation ;  it  is 
then  transitory,  lasting  only  for  some  weeks  or 
months.  While  the  habit  endures  the  fits  never 
occur  spontaneously,  but  only  as  a  result  of  irritating 
a  small  area  of  skin  behind  the  ear  on  the  same  side  of 


Characters^  Hereditary  and  Acquired.  115 

the  body  as  that  on  which  the  sciatic  nerve  had  been 
divided.  Effectual  irritation  may  be  either  mechan- 
ical (such  as  gentle  pinching),  electrical,  or,  though 
less  certainly,  thermal.  The  area  of  skin  in  question, 
scon  after  the  epileptiform  habit  .supervenes,  and 
during  all  the  time  that  it  lasts,  swarms  vvith  lice 
of  the  kind  which  infest  guinea-pigs— i.e.  the  lice 
congregate  in  this  area,  on  account,  I  think,  of  the 
animal  being  there  insensitive,  and  therefore  not 
disturbing  its  parasites  in  that  particular  spot ;  other- 
wise it  would  presumably  throw  itself  into  fits 
by  scratching  that  spot.  On  removing  the  skin  from 
the  area  in  question,  no  kind  or  degree  of  irritation 
supplied  to  the  subjacent  tissue  has  any  effect  in  pro- 
ducing a  fit  A  fit  never  lasts  for  more  than  a  very 
few  minutes,  during  which  the  animal  is  unconscious 
and  convulsed,  though  not  with  any  great  violence.  The 
epileptiform  habit  is  but  rarely  transmitted  to  progeny. 
Most  of  these  observations  are  in  accordance  with 
those  previously  made  by  IVown-Sequard,  and  also 
by  others  who  have  repeated  his  experiments  under 
this  heading.  I  can  have  no  doubt  that  the  injury 
of  the  sciatic  nerve  or  spinal  cord  produces  a  change 
in  some  of  the  cerebral  centres,  and  that  it  is 
this  change — whatever  it  is  and  in  whatever  part 
of  the  brain  it  takes  place — which  causes  the  re- 
markable phenomena  in  question. 

3rd.  A  change  in  the  shape  of  the  ear  in  animals  bom  of 
parents  in  which  such  a  change  was  the  effect  of  a  division 
of  the  cervical  sympathetic  nerve. 

4th.  Partial  closure  of  the  eyelids  in  animals  born  of  parents 
in  which  that  state  of  the  eyelids  had  been  caused  either  by 
section  of  the  cervical  sympathetic  nerve,  or  the  removal  uf  the 
superior  cer/ical  ganglion. 

I  2 


\ 


Hi 

11 


1 


I 


ii6        Darwin,  and  after  Darwin, 


I' 

f 


if 


"». 


% 


pit: 

Sir 


I  have  not  succeeded  in  corroborating  these  results. 
It  must  be  added,  however,  that  up  to  the  time  of 
going  to  press  my  experiments  on  this,  the  easiest 
branch  of  the  research,  have  been  too  few  fairly  to 
prove  a  negative. 

5th.  Exophthalmia  in  animals  born  of  parents  in  which  an 
injury  to  the  restifortn  body  had  produced  that  protrusion  of  the 
eyeball.  ...  In  these  animals,  modified  by  heredity,  the  two 
eyes  generally  protruded,  although  in  the  parents  usually  only 
one  showed  exophthalmia,  the  lesion  having  been  made  in  most 
cases  only  on  one  of  the  corpora  restiformia. 

I  have  fully  corroborated  the  statement  that 
injury  to  a  particular  spot  of  the  restiform  body  is 
quickly  followed  by  a  marked  protrusion  of  the  eye- 
ball on  the  same  side.  I  have  also  had  many  cases 
in  which  some  of  the  progeny  of  parents  thus  affected 
have  shown  considerable  protrusion  of  the  eyeballs  on 
both  sides,  and  this  seemingly  abnormal  protrusion 
has  been  occasionally  transmitted  to  the  next  gener- 
ation. Nevertheless,  I  am  far  from  satisfied  that 
this  latter  fact  is  anything  more  than  an  accidental 
coincidence.  For  I  have  never  seen  the  so-called  ex- 
ophthalmia of  progeny  exhibited  in  so  high  a  degree 
as  it  occurs  in  the  parents  as  an  immediate  result 
of  the  operation,  while,  on  examining  any  large 
stock  of  normal  guinea-pigs,  there  is  found  a  con- 
siderable amount  of  individual  variation  in  regard 
to  prominence  of  eyeballs.  Therefore,  while  not 
denying  that  the  obviously  abnormal  amount  of 
protrusion  due  to  the  operation  may  be  inherited 
in  lesser  degrees,  and  thus  may  be  the  cause  of  the 
unusual  degree  of  prominence  which  is  sometimes 
seen  in  the  eyeballs  of  progeny  born  of  exophthalmic 


Characters f  Hereditary  and  Acquired.  117 

parents,  I  am  unable  to  affirm  so  important  a  con- 
clusion on  the  basis  supplied  by  these  experiments. 

6th.  Haematoma  and  dry  gangrene  of  the  ears  in  animals 
bom  of  parents  in  which  these  ear-alterations  had  been  caused 
by  an  injury  to  the  restiform  body. 

As  regards  the  animals  operated  upon  (1.  e.  the 
parents),  I  find  that  the  haematoma  and  dry  gan- 
grene may  supervene  either  several  weeks  after  the 
operation,  or  at  any  subsequent  time  up  to  many 
months.  When  it  does  supervene  it  usually  afifects 
the  upper  parts  of  both  ears,  and  may  then  eat  its 
way  down  until,  in  extreme  cases,  it  has  entirely 
consumed  two-thirds  of  the  tissue  of  both  ears. 
As  regards  the  progeny  of  animals  thus  affected, 
in  some  cases,  but  by  no  means  in  all,  a  similarly 
morbid  state  of  the  ears  may  arise  apparently 
at  any  time  in  the  life-history  of  the  individual. 
But  I  have  observed  that  in  cases  where  two  or 
more  individuals  of  the  same  litter  develop  this 
diseased  condition,  they  usually  do  so  at  about  the 
same  time — even  though  this  be  many  months  after 
birth,  and  therefore  after  the  animals  are  fully  grown. 
But  in  progeny  the  morbid  process  never  goes  so 
far  as  in  the  parents  which  have  been  operated 
upon,  and  it  almost  always  affects  the  middle  thirds 
of  the  ears.  In  order  to  illustrate  these  points,  repro- 
ductions of  two  of  my  photographs  are  appended. 
They  represent  the  consequences  of  the  operation  on 
a  male  and  a  female  guinea-pig.  Among  the  progeny 
of  both  these  animals  there  were  several  in  which 
a  portion  of  eacli  ear  was  consumed  by  apparently  the 
same  process,  where,  of  course,  there  had  been  no 
operation. 


i 


'1 


I 

I 

<^ 
»  2.' 

'  H 

1 


~<«»>^«K''«HB»-  ^  ^. 


k.  VI- 


Ir 


{.' 


[f  -  ^  Si 

'»* 


<il 


Fig.  I. — Reproduction  of  photographs  from  life  of  a  male  and  female 
guinea-pig,  whose  left  restiform  bodies  had  been  injured  by  a  scalpel 
six  months  previously.  The  loss  of  tissue  in  both  ears  was  due  to 
haematoma  and  dry  gangrene,  which,  however,  had  ceased  when  the 
photograph  was  taken. 


1 1: 


Characters f  Hereditary  and  Acquired.  119 

It  should  be  observed  that  not  only  is  a  different  part 
of  the  ear  affected  in  the  progeny,  but  also  a  very 
much  less  quantity  thereof.  Naturally,  therefore,  the 
hypothesis  of  heredity  seems  less  probable  than  that 
of  mere  coincidence  on  the  one  hand,  or  of  transmitted 
microbes  on  the  other.  But  I  hope  to  have  fairly 
excluded  both  these  alternative  explanations.  For, 
as  regards  merely  accidental  coincidence,  I  have 
never  seen  this  very  peculiar  morbid  process  in  the  ears, 
or  in  any  other  parts,  of  guinea-pigs  which  have 
neither  themselves  had  their  restiform  bodies  in- 
jured, nor  been  born  of  parents  thus  mutilated.  As 
regards  the  hypothesis  of  microbes,  I  have  tried  to 
inoculate  the  corresponding  parts  of  the  ears  of 
normal  guinea-pigs,  by  first  scarifying  those  parts 
and  then  rubbing  them  with  the  diseased  surfaces  of 
the  ears  of  mutilated  guinea-pigs  ;  but  have  not  been 
able  in  this  way  to  communicate  the  disease. 

It  will  be  seen  that  the  above  results  in  large 
measure  corroborate  the  statements  of  Brown- 
Sdquard  ;  and  it  is  only  fair  to  add  that  he  told  me 
they  are  the  results  which  he  had  himself  obtained 
most  frequently,  but  that  he  had  also  met  with  many 
cases  where  the  diseased  condition  of  the  ears  in 
parents  affected  the  same  parts  in  their  progeny,  and 
also  occurred  in  more  equal  degrees.  Lastly,  I  should 
like  to  remark,  with  regard  to  these  experiments  on 
restiform  bodies,  and  for  the  benefit  of  any  one  else  who 
may  hereafter  repeat  them,  that  it  will  be  necessary 
for  him  to  obtain  precise  information  touching  the 
modus  operandi.  For  it  is  only  one  very  localized 
spot  in  each  restiform  body  which  has  to  be  injured  in 
order   to   produce   any   of   the   results   in   question. 


'H 


^1 


1 


120         Darwin,  and  after  Darwin 


I; 
I' 


'S* 


^l. 


I  myself  lost  two  years  of  work  on  account  of  not 
knowing  this  exact  spot  before  going  to  Paris  for  the 
purpose  of  seeing  Brown-Scquard  himself  perform 
the  operation.  I  had  in  the  preceding  year  seen  one 
of  his  assistants  do  so,  but  this  gentleman  had  a  much 
more  careless  method,  and  one  which  in  my  hands 
yielded  uniformly  negative  results.  The  exact  spot 
in  question  in  the  restiforin  body  is  as  far  forwards  as 
it  is  possible  to  reach,  and  as  far  down  in  depth  as  is 
compatible  with  not  producing  rotatory  movements. 

7th.  Absence  of  two  toes  out  of  the  three  of  the  hind  leg,  and 
sometimes  of  the  three,  in  animals  whose  parents  bad  eaten  up 
their  hind-leg  toes  which  had  become  anaesthetic  from  a  section 
of  the  sciatic  nerve  alone,  or  of  that  nerve  and  also  of  the  crural. 
Sometimes,  instead  of  complete  absence  of  the  toes,  only  a  part 
of  one  or  two  or  three  was  missing  in  the  young,  although  in  the 
parent  not  only  the  toes  but  the  whole  foot  were  absent. 

As  I  found  that  the  results  here  described  were 
usually  given  by  division  of  the  sciatic  nerve  alone — 
or,  more  correctly,  by  excision  of  a  considerable  por- 
tion of  the  nerve,  in  order  to  prevent  regeneration — 
I  did  not  also  divide  the  crural.  But,  although  I  have 
bred  numerous  litters  from  parents  thus  injured,  there 
has  been  no  case  of  any  inherited  deficiency  of  toes. 
My  experiments  in  this  connexion  were  carried  on 
through  a  series  of  six  successive  generations,  so  as  to 
produce,  if  possible,  a  cumulative  effect.  Nevertheless, 
no  effect  of  any  kind  was  produced.  On  the  other 
hand,  Brown-S^quard  informed  me  that  he  had 
observed  this  inherited  absence  of  toes  only  in  about 
one  or  two  per  cent,  of  cases.  Hence  it  is  pos- 
sible enough,  that  my  experiments  have  not  been 
sufficiently  numerous  to  furnish  a  ccise.     It  may  be 


'i 


Characters,  Hereditary  and  Acquired.  121 

added  that  there  is  here  no  measurable  possibility 
of  accidental  coincidence  (seeing  that  normal  guinea- 
pigs  do  not  seem  ever  to  produce  young  with  any 
deficiency  of  toes),  while  the  only  possibility  of 
mal-observation  consists  in  some  error  with  regard 
to  the  isolation  (or  the  tabulation)  of  parents  and 
progeny.  Such  an  error,  however,  may  easily  arise. 
For  ga.  grene  of  the  toes  does  not  set  in  till  some 
considerable  time  after  division  of  the  sciatic  nerve. 
Hence,  if  the  wound  be  healed  uefore  the  gangrene 
begins,  and  if  any  mistake  has  been  made  with  re- 
gard to  the  isolation  (or  tabulation)  of  the  animal,  it 
becomes  possible  that  the  latter  should  be  recorded 
as  an  uninjured;  instead  of  an  injured,  individual.  On 
this  account  one  would  like  to  be  assured  that 
Brown-Sdquard  took  the  precaution  of  examining 
the  state  of  the  sciatic  nerve  in  those  comparatively 
few  specimens  which  he  alleges  to  have  displayed 
such  exceedingly  definite  proof  of  the  inheritance 
of  a  mutilation.  For  it  is  needless  tG  remark,  after 
what  has  been  said  in  the  preceding  chapter  on  the 
analogous  case  of  epilepsy,  that  the  proof  would 
not  be  regarded  by  any  physiologist  as  displaced 
by  the  fact  that  there  is  no  observable  deficiency 
in  the  sciatic  nerve  of  the  toeless  young. 

8th.  Appearance  of  various  morbid  states  of  the  skin  and 
hair  of  the  neck  and  face  in  animals  bom  of  parents  having  liad 
similar  alterations  in  the  same  parts,  as  effects  of  an  injury  to 
the  sciatic  nerve. 

I  have  not  paid  any  attention  to  this  paragraph, 
because  the  facts  which  it  alleges  did  not  seem  of 
a  sufficiently  definite  character  to  serve  as  a  guide  to 
further  experiment. 


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122         Darwin,  and  after  Darwin. 


I' ; 


"■  -^ 


On  the  whole,  then,  as  regards  Brown-S^quard's 
experiments,  it  will  be  seen  that  I  have  not  been 
able  to  furnish  any  approach  to  a  full  corroboration. 
But  I  must  repeat  that  my  own  experiments  have 
not  as  yet  been  sufficiently  numerous  to  justify 
me  in  repudiating  those  of  his  statements  which 
I  have  not  been  able  to  verify. 

The  only  other  experimental  results,  where  animals 
are  concerned,  which  seemed  to  tell  on  the  side  of 
Lamarckianism,  are  those  of  Mr.  Cunningham,  already 
alluded  to.  But,  as  the  research  is  still  in  progress, 
the  school  of  Weismann  may  fairly  say  that  it  would 
be  premature  to  discuss  its  theoretical  bearings. 


I, 


Passing  now  from  experiments  on  animals  to 
experiments  on  plants,  I  must  again  ask  it  to  be 
borne  in  mind,  that  here  also  no  researches  have 
been  published,  which  have  had  for  their  object  the 
testing  of  the  question  on  which  we  are  engaged. 
As  in  the  case  of  animals,  therefore,  so  in  that  of 
plants,  we  are  dependent  for  any  experimental  results 
bearing  upon  the  subjec*"  to  such  as  have  been  gained 
incidentally  during  the  course  of  investigations  in 
quite  other  directions. 

Allusion  has  already  been  made,  in  my  previous 
essay,  to  De  Vries"  observations  on  the  chromatophores 
of  algae  passing  from  the  ovum  of  the  mother  to 
the  daughter  organism ;  and  we  have  seen  that 
even  Weismann  admits,  ^'  It  appears  possible  that 
a  transmission  of  somatogenetic  variation  has  here 
occurred  ^."  It  will  now  be  my  object  to  show  that 
such  variations  appear  to  be  sometimes  transmitted 
'  ExamintUion  of  Weismannism,  p.  83. 


Characters  J  Hereditary  and  Acquired.  123 

in  the  case  of  higher  plants,  and  this  under  circum- 
stances which  carry  much  less  equivocal  evidence 
of  the  inheritance  of  acquired  characters,  than  can 
be  rendered  by  the  much  more  simple  organization 
of  an  alga. 

I  have  previously  mentioned  Hoffmann's  experi- 
ments on  transplantation,  the  result  of  which  was 
to  show  that  variations,  directly  induced  by  changed 
conditions  of  life,  were  reproduced  by  seed  \  Weis- 
mann,  however,  as  we  have  seen,  questions  the 
somatogenetic  origin  of  these  variations — attributing 
the  facts  to  a  blastogenetic  change  produced  in  the 
plants  by  a  direct  action  of  the  changed  conditions 
upon  the  germ-plasm  itself^.  And  he  points  out 
that  whether  he  is  right  or  wrong  in  this  inter- 
pretation can  only  be  settled  by  ascertaining  whether 
the  observable  somatic  changes  occur  in  the  genera- 
tion which  is  first  exposed  to  the  changed  conditions 
of  life.  If  they  do  occur  in  the  first  generation,  they 
are  somatogenetic  changes,  which  afterwards  re-act 
on  the  substance  of  heredity,  so  as  to  transmit  the 
acquired  peculiarities  to  progeny.  But  if  they  do 
not  occur  till  the  second  (or  any  later)  generation, 
they  are  presumably  blastogenetic.  Unfortunately 
Hoffmann  does  not  appear  to  have  attended  to 
this  point  with  sufficient  care,  but  there  are  other 
experiments  of  the  same  kind  where  the  point  has 
been  specially  observed. 

For  instance j  M.  L.  A.  Carri^re  '  gathered  seed  from 
the  wild  radish  {Raphanus  Raphanistrum)  in  France, 

*  Examination  of  Weismannism,  p.  93.  '  Ibid.  p.  153 

•  Origim  des  Plantes  Domestiques,  fUmmtrie  par  la  culture  du  Radis 
SoMvt^  (Paris,  i869\ 


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124         Darwm,  and  after  Darwin, 

and  sowed  one  lot  in  the  light  dry  soil  near  the 
Museum  of  Natural  History  in  Paris,  while  another 
lot  was  sown  by  him  at  the  same  time  in  heavy 
soil  elsewhere.  His  object  was  to  ascertain  whether 
he  could  produce  a  good  cultivated  radish  by 
methodical  selection  ;  and  this  he  did,  in  a  wonder- 
fully rapid  manner,  during  the  course  of  a  very  few 
generations.  But  the  point  for  us  is,  that  from  the 
first  the  plants  grown  in  the  light  soil  of  Paris 
presented  sundry  marked  differences  from  those 
grown  in  the  heavy  soil  of  the  country ;  and  that 
these  points  of  difference  had  nothing  to  do  with 
the  variations  on  which  his  artificial  selection  was 
brought  to  bear.  For  while  his  artificial  selection 
was  directed  to  increasing  the  size  of  the  "root," 
the  differences  in  question  had  reference  to  \Xs>  form 
and  colour.  In  Paris  an  elongated  form  prevailed, 
which  presented  either  a  white  or  a  rose  colour :  in 
the  country  the  form  was  more  rounded,  and  the 
colour  violet,  dark  brown,  or  "  almost  black."  Now, 
as  these  differences  were  strongly  apparent  in  the 
first  generation,  and  were  not  afterwards  made  the 
subject  of  selection,  both  in  origin  and  development 
they  must  have  been  due  to  "  climatic  "  influences 
acting  on  the  somatic  tissues.  And  although  the  author 
does  not  appear  to  have  tested  their  hereditary  char- 
acters by  afterwards  sov/ing  the  seed  from  the  Paris 
variety  in  the  country,  or  vice  versa,  we  may 
fairly  conclude  that  these  changes  must  have  been 
hereditary — ist,  from  the  fact  of  their  intensification 
in  the  course  of  the  five  sequent  generations  over 
which  the  experiment  extended,  and,  2nd,  from  the 
very  analogous  results  which  were  similarly  obtained 


Characters f  Hereditary  and  Acquired.  125 


in  the  following  case  with  another  genus,  where 
both  the  somatogenetic  and  the  hereditary  characters 
of  the  change  were  carefully  and  specially  observed. 
This  case  is  as  follows. 

The  late  Professor  James  Buckman.  F.R.S.,  saved 
some  seed  from  wild  parsnips  {P.  sativa)  in  the 
summer  of  1847,  and  sowed  under  changed  conditions 
of  life   in   the  spring  184H.     The  plants    grown 

from  these  wild  sect.  >  were  for  the  most  part  like 
wild  plants ;  but  some  of  them  had  "  already 
(i.e.  in  the  autumn  of  1848)  the  light  green  and 
smooth  aspect  devoid  of  hairs  which  is  peculiar  to 
the  cultivated  plant ;  and  among  the  latter  there 
were  a  few  with  longer  leaves  and  broader  divisions 
of  leaf-lobes  than  the  rest — the  leaves,  too,  all  grow- 
ing systematically  round  one  central  bud.  The  roots 
of  the  plant  when  taken  up  were  observed  to  be 
for  the  most  part  more  fleshy  than  those  of  wild 
examples  V 

Professor  Buckman  '  ;ien  proceeds  to  describe  how 
he  selected  the  best  samples  for  cultivation  in 
succeeding  generations,  till  eventually  the  variety 
which  he  called  "  The  Student "  was  produced,  and 
which  Messrs.  Sutton  still  regard  as  the  best  variety 
in  their  catalogue.  That  is  to  say,  it  has  come 
true  to  seed  for  the  last  forty  years ;  and  although 
such  great  excellence  and  stability  are  doubtless  in 
chief  part  due  to  the  subsequent  process  of  selec- 
tion by  Professor  Buckman  in  the  years  1848-1850, 
this  does  not  affect  the  point  with  which  we  are 
here  concerned — namely,  that  the  somatogenetic 
changes  of  the   plants   in  the  first  generation  were 

'  Jouml.  Agric.  Soc.  1848. 


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126         Darwm,  and  after  Darwin, 

transmitted  by  seed  to  the  second  generation, 
and  thus  furnished  Professor  Buckman  with  the 
material  for  his  subsequent  process  of  selection. 
And  the  changes  in  question  were  not  merely  ot 
a  very  definite  character,  but  also  of  what  may  be 
termed  a  very  local  character — affecting  only  par- 
ticular tissues  of  the  soma,  and  therefore  expressive 
of  a  high  degree  of  representation  on  the  part  of  the 
subsequently  developed  seed,  by  which  they  were 
faithfully  reproduced  in  the  next  generation. 

Here  is  another  case.  M.  Lesage  examined  the 
tissues  of  a  large  number  of  plants  growing  both 
near  to,  and  remote  from,  the  sea.  He  suspected 
that  the  characteristic  fleshiness,  &c.  of  seaside  plants 
was  due  to  the  influence  of  sea-salt ;  and  proved  that 
such  was  the  case  by  causing  the  characters  to 
occur  in  inland  plants  as  a  result  of  watering  them 
with  salt-water.     Then  he  adds : — 

"J'ai  rdussi  surtout  pour  le  Lepidium  sativum  cultiv^  en 
1888 ;  j'ai  obtenu  pour  la  m^me  plante  des  rdsultats  plus  nets 
encore  dans  la  culture  de  1889,  entreprise  en  semant  les  graines 
ff^coltdes  avec  soin  des  pots  de  I'aniide  prdc^dente  et  trait^es 
exactement  de  la  meme  fa5on^  " 

Here,  it  will  be  observed,  there  was  no  selec- 
tion; and  therefore  the  increased  hereditary  effect 
in  the  second  generation  must  apparently  be  ascribed 
to  a  continuance  of  influence  exercised  by  somatic 
tissues  on  germinal  elements ;  for  at  the  time  when 
the  changes  were  produced  no  seed  had  been  formed. 
In  other  words,  the  accumulated  change,  like  the 
initial  change,  would  seem  to  have  been  exclusively 
of  somatogenetic  origin  ;  and  yet  it  so  influenced  the 

'  Reo.  Gen.  de  Bot.  torn.  ii.  p.  64. 


P 


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Characters f  Hereditary  and  Acquired.  127 

qualities  of  the  seed  (as  this  was  aftci  wards  formed), 
that  the  augmented  changes  were  transmitted  to  the 
next  generation,  part  for  part,  as  the  lesser  changes  had 
occurred  in  the  preceding  generation.  "  This  experi- 
ment, therefore,  like  Professor  Ruckman's,  shows  that 
the  alteration  of  the  tissues  was  carried  on  in  the 
second  generation  from  the  point  gained  in  the  first. 
In  both  cases  no  germ-plasm  (in  the  germ-cells) 
existed  at  the  time  during  which  the  alterations 
arose,  as  they  were  confined  to  the  vcj^etative  system; 
and  in  the  case  of  the  parsnips  anc'  carrots,  being 
biennials  no  germ-cells  are  produced  till  the  second 
year  has  arrived  ^." 

Once  more.  Professor  Bailey  remarks: — 

"Squashes  often  show  remarkable  differences  when  grown 
upon  different  soils;  and  these  differences  can  sometimes  be  per- 
petuated for  a  time  by  seeds.  The  writer  has  produced,  from 
the  same  parent,  squashes  so  dissimilar,  through  the  simple 
agency  of  a  change  of  soil  in  one  season,  that  they  might  readily 
be  taken  for  distinct  varieties.  Peas  are  known  to  vary  in  the 
same  manner.  The  seeds  of  a  row  of  peas  of  the  same  kind, 
last  year  gave  the  writer  marked  variations  due  to  differences 

of  soil Pea-growers  characterize  soils   as  *  good '   and 

'viney.'  Upon  the  latter  sort  the  plants  run  to  vine  at  the 
expense  of  the  fruit,  and  their  offspring  for  two  or  three 
generations  have  the  same  tendency  '*." 

I  think  these  several  cases  are  enough  to  show 
that,  while  the  Weismannian  assumption  as  to  the 
seeming  transmission  of  somatogenetic  characters 
being   restricted    to  the    lowest    kinds  of  plants   is 


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*  I  am  indebted  to  the  Rev.  G.  Henslow  for  the  references  to 
these  cases.  This  and  the  passages  which  follow  are  quoted  from  his 
letters  to  me. 

-  Gardener's  Chronicle,  May  31,  1890,  p.  677. 


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128         Darwin,  and  after  Darwin, 

purely  gratuitous,  there  is  no  small  amount  of 
evidence  to  the  contrary — or  evidence  which  seems 
to  prove  that  a  similar  transmission  occurs  likewise 
in  the  higher  plants.  And  no  doubt  many  additional 
cases  might  be  advanced  by  any  one  who  is  well 
read  in  the  literature  of  economic  botany. 

It  appears  to  me  that  the  only  answer  to  such  cases 
would  be  furnished  by  supposing  that  the  heredi- 
tary changes  are  due  to  an  alteration  of  the  residual 
"  germ-plasm "  in  the  wild  seed,  when  this  is  first 
exposed  to  the  changed  conditions  of  life,  due  to 
its  growth  in  a  strange  kind  of  soil— e.  g.  while  ger- 
minating in  an  unusual  kind  of  earth  for  producing  the 
first  generation.  But  this  would  be  going  a  long 
way  to  save  an  hypothesis.  In  case,  however,  it 
should  now  be  suggested,  I  may  remark  that  it 
would  be  negatived  by  the  following  facts  ^ 

In  the  first  place,  an  endless  number  of  cases  might 
be  quoted  where  somatogenetic  changes  thus  pro- 
duced by  changed  conditions  of  life  are  not  hereditary. 
Therefore,  in  all  these  cases  it  is  certainly  not  the 
"  germ-plasm  "  that  is  afiected.  In  other  words,  there 
can  be  no  question  that  somatogenetic  changes  of  the 
k'nds  above  mentioned  do  very  readily  admit  of  being 
produced  in  the  first  generation  by  changes  of  soil, 
altitude,  &c.  And  that  somatogenetic  changes  thus 
produced  should  not  always — or  even  generally — 
prove  themselves  to  be  hereditary  from  the  first 
moment  of  their  occurrence,  is  no  more  than  any  theory 

*  Since  the  above  was  written  Professor  Weismann  has  advanced,  in 
The  Germ-plasm^  a  suggestion  very  similar  to  this.  It  is  sufficient  here 
to  remark,  that  nearly  all  the  facts  and  considerations  which  ensue  in 
the  present  chapter  are  applicable  to  his  suggestion,  the  essence  of  which 
is  anticipated  in  the  above  | paragraph. 


Characters,  Hereditary  and  Acquired.  129 

of  heredity  woulrl  expect.  Indeed,  looking  to  the 
known  potency  of  reversion,  the  wonder  is  that  in  any 
case  such  changes  sliould  become  hereditary  in  a  single 
generation.  On  the  otlicr  liand,  there  is  no  reason  to 
imagine  that  the  hypothetical  germ-plasm — howsoever 
unstable  we  may  suppose  it  to  be — can  admit  of  being 
directly  affected  by  a  change  of  soil  in  a  single 
generation.  For,  on  this  view,  it  must  presumably  be 
chiefly  affected  during  the  short  time  that  the  seed  is 
germinating ;  and  during  that  time  the  changed  con- 
ditions can  scarcely  be  conceived  as  having  any  points 
of  attack,  so  to  speak,  upon  the  residual  germ-plasm. 
There  arc  no  roots  on  which  the  change  of  soil  can 
make  itself  perceptible,  nor  any  stem  and  leaves  on 
which  the  change  of  atmosphere  can  operate.  Yet  the 
changed  conditions  may  produce  hereditary  modifica- 
tions in  any  parts  of  the  plant,  which  are  not  only 
preciselyanalogous  to  non-hereditary  changes  similarly 
produced  in  the  somatic  tissues  of  innumerable  other 
plants,  but  are  always  of  precisely  the  same  kind  in 
the  same  lot  of  plants  that  are  affected.  When  all  the 
radishes  grown  from  wild  seed  in  Paris,  for  instance, 
varied  in  the  direction  of  rotundity  and  dark  colour, 
while  those  grown  in  the  country  presented  the  opposite 
characters,  we  can  well  understand  the  facts  as  due 
to  an  entire  season's  action  upon  the  whole  of  the 
growing  plant,  with  the  result  that  all  the  changes 
produced  in  each  set  of  plants  were  similar — ^just  as 
in  the  cases  where  similarly  '  climatic  "  modifications 
are  not  hereditary,  and  therefore  unquestionably  due 
to  changed  conditions  acting  on  roots,  stems,  leaves, 
or  flowers,  as  the  case  may  be.  On  the  other  hand, 
it    is    not    thus    intelligible    that    during  the  short 

II.  K 


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130        Darwin f  and  after  Darwin. 


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time  of  germination  the  changed  conditions  should 
effect  a  re-shuffling  'or  any  other  modification)  of 
the  "  germ-plasm  "  in  the  seeds — and  this  in  such 
a  manner  that  the  effect  on  the  residual  germ-plasm 
reserved  for  future  generations  is  precisely  similar  to 
that  produced  on  the  somatic  tissues  of  the  developing 
embryo. 

In  the  second  place,  as  we  have  seen,  in  some  of 
the  foregoing  cases  the  changes  were  produced 
months — and  even  years — before  the  seeds  of  the  first 
germination  were  formed.  Therefore  the  hereditary 
effect,  if  subsequent  to  the  period  of  embryonic  ger- 
mination, must  have  been  produced  on  germ-plasm 
as  this  occurs  diffused  through  the  somatic  tissues. 
But,  if  so,  we  shall  have  to  suppose  that  such  germ- 
plasm  is  afterwards  gathered  in  tlie  seeds  when  these 
are  subsequently  formed.  This  supposition,  however, 
would  be  radically  opposed  to  Weismann's  theory  of 
heredity :  nor  do  I  know  of  any  other  theory  with 
which  it  would  be  reconcilable,  save  such  as  entertain 
the  possibility  of  the  Lamarckian  factors. 

Lastly,  in  the  third  p'ace,  I  deem  the  following 
considerations  of  the  highest  importance : — 

"As  other  instances  in  which  peculiar  structures  are  now 
hereditary  may  be  mentioned  aquatic  plants  and  those  producing 
subterraneous  stems.  Whether  they  be  dicotyledons  or  mono- 
cotyledons, there  is  a  fundamental  agreement  in  the  anatomy 
of  the  roots  and  stem  of  aquatic  plants,  and,  in  many  cases,  of 
the  leaves  as  wdl.  Such  has  hitherto  been  attributed  to  the 
aquatic  habit.  The  inference  or  deduction  was,  of  course,  based 
upon  innumerable  coincidences ;  the  water  being  supposed  to 
be  the  direct  cause  of  the  degenerate  structures,  which  are 
hereditary  and  characteristic  of  such  plants  in  the  wild  state 
M.  Costantin  has,  however,  verified  this  deduction,  by  making 


Characters f  Hereditary  and  Acquired,  131 

terrestrial  and  aerial  steins  to  grow  underground  and  in  water : 
the  structures  at  once  began  to  assume  the  subterranean  or 
aquatic  type,  as  the  case  might  be :  and,  conversely,  aquatic 
plants  made  to  grow  upon  land  at  once  began  to  assume  the 
terrestrial  type  of  structure,  while  analogous  results  followed 
changes  from  a  subterranean  to  an  aerial  position,  and  vice 
versa.'* 

This  is  also  quoted  from  the  Rev.  Prof.  Henslow's 
letters  to  me,  and  the  important  point  in  it  is,  that 
the  great  changes  in  question  are  proved  to  be  of 
a  purely  "  somatogenetic  "  kind  ;  for  they  occurred  *•  at 
once "  in  the  ready-grown  plants  when  the  organs 
concerned  were  exposed  to  the  change  from  aquatic 
to  terrestrial  life,  or  vice  versa — and  also  from  a  sub- 
terranean to  an  aerial  position,  or  vice  versa.  Con- 
sequently, even  the  abstract  possibility  of  the  changed 
conditions  of  life  having  operated  on  the  seed  is  here 
excluded.  Yet  the  changes  are  of  precisely  the  same 
kind  as  are  now  hereditary  in  the  wild  species.  It 
thus  appears  undeniable  that  all  these  remarkable  and 
uniform  changes  must  originally  have  been  somato- 
genetic changes ;  yet  they  have  nov;  become  blasto- 
genetic.  This  much,  I  say,  seems  undeniable  ;  and 
therefore  it  goes  a  long  way  to  prove  that  the  non- 
blastogenetic  character  of  the  changes  has  been  due 
to  their  originally  somatogenetic  character.  For,  if 
not,  how  did  natural  selection  ever  get  an  opportunity 
of  making  any  of  them  blastogenetic,  when  every 
individual  plant  has  always  presented  them  as  already 
given  somatogenetically  ?  This  last  consideration 
appears  in  no  small  measure  to  justify  the  opinion  of 
Mr.  Henslow,  who  concludes — "These  experiments 
prove,  not  only  that  the  influence  of  the  environment 

K  2 


11: 


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1» 


"^  1. 


132         Darwm,  and  after  Darwin. 

is  at  once  felt  by  the  organ  ;  but  that  it  is  indubitably 
the  cause  of  the  now  specific  and  hereditary  traits 
peculiar  to  normally  aquatic,  subterranean,  and 
aerial  stems,  or  roots  *." 

He  continues  to  furnish  other  instances  in  the  same 
line  of  proof — such  as  the  distinctive  *  habits "  of 
insectivorous,  parasitic,  and  climbing  plants ;  the 
difference  in  structure  between  the  upper  and  under 
sides  of  horizontal  leaves.  &c.  "  For  here,  as  in  all 
organs,  we  discover  by  experiment  how  easily  the 
anatomy  of  plants  can  be  affected  by  their  environ- 
jnent ;  and  that,  as  long  as  the  latter  is  constant,  so  are 
the  characters  of  the  plants  constant  and  hereditary." 


"iKs 


'Vii 


!:: 


*  It  also  serves  to  show  that  Weismann's  newer  doctrine  of  similar 
"determinants"  occurring  both  in  the  germ  and  in  the  somatic  tissues 
is  a  doctrine  which  cannot  be  applied  to  rebut  this  evidence  of  the 
transmission  of  acquired  characters  in  plants.  Therefore  even  its 
hypothetical  validity  as  applied  by  him  to  explain  the  seasonal  variation 
of  butterflies  is  rendered  in  a  high  degree  dubious. 

[The  following  letter,  contributed  by  Dr.  Hill  to  A^atur*,  vol.  1.  p.  617, 
may  here  be  quoted.     C.  LI.  M. 

"  It  may  be  of  interest  to  your  readers  to  know  that  two  guinea-pigs 
were  bom  at  Oxford  a  day  or  two  before  the  death  Dr.  Romanes,  both 
of  which  exhibited  a  well-marked  droop  of  the  left  upper  eye-lid.  These 
guinea-pigs  were  the  offspring  of  a  male  and  a  female  guinea-pig  in  both 
of  which  1  had  produced  for  Dr.  Romanes,  some  months  earlier,  a  droop 
of  the  left  upper  eyelid  by  division  of  the  left  cervical  sympathetic  nerve. 
This  result  is  a  corroboration  of  the  series  of  Brown-Sequard's  experi- 
ments on  the  inheritance  of  acquired  characteristics.  A  very  large  series 
of  such  experiments  are  of  course  needed  to  eliminate  all  sources  of  error, 
but  this  I  unfortunately  cannot  carry  out  at  present,  owing  to  the  need  of 
a  special  farm  in  the  country,  for  the  proper  care  and  breeding  of  the 
animals. — Leonard  Hill. 

•♦Physiological  Laboratory^  Univ.  Coll.  London,  Oct.  18,  1894."] 


CHAPTER  V. 

Characters  as  Hereditary  and  Acquired 

(continued). 

(A.  and  B.) 

Direct  and  Indirect  Evidence  in  favour  of  the  Non- 
inheritance  of  Acquired  Characters  ^. 

The  strongest  argument  in  favour  of  "  continuity '' 
is  that  based  upon  the  immense  difference  between 
congenital  and  acquired  characters  in  respect  of 
heritability.  For  that  there  is  a  great  difference 
in  this  respect  is  a  matter  of  undeniable  fact.  And 
it  is  obvious  that  this  difference,  the  importance  of 
which  must  be  allowed  its  full  weight,  is  just  what 
we  should  expect  on  the  theory  of  the  continuity  of 
the  germ-plasm,  as  opposed  to  that  of  pangenesis. 
Indeed  it  may  be  said  that  the  difference  in  question, 
while  it  constitutes  important  evidence  in  favour  of 
the  former  theory,  is  a  difficulty  in  the  way  of  the 
latter.  But  here  two  or  three  considerations  must  be 
borne  in  mind. 

In  the  first  place,  this  fact  has  long  been  one  which 
has  met  with  wide  recognition  and  now  constitutes 
the  main  ground  on  which  the  theory  of  continuity 

'  \_See  note  appended  to  Preface.     C.  LI.  M.] 


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134        Darzvm,  and  after  Darwin, 

stands.  That  is  to  say,  it  was  the  previous  know- 
ledge of  this  contrast  between  congenital  and  acquired 
characters  which  led  to  the  formulation  of  a  theory  of 
continuity  by  Mr.  Galton,  and  to  its  subsequent 
development  by  Prof.  Weismann. 

But,  in  the  second  place,  there  is  a  wide  difference 
between  the  certainty  of  this  fact  and  that  of  the 
theory  based  upon  it.  The  certain  fact  is,  that 
a  great  distinction  in  respect  of  heritability  is 
observable  between  congenital  and  acquired  char- 
acters. The  theory,  as  formulated  by  Weismann,  is 
that  the  distinction  is  not  only  great  but  absolute,  or, 
in  other  words,  that  in  no  case  and  in  no  degree 
can  any  acquired  character  be  ever  inherited.  This 
hypothesis,  it  will  be  observed,  goes  far  beyond  the 
observed  fact,  for  it  is  obviously  possible  that,  not- 
withstanding this  great  difference  in  regard  to  herita- 
bility between  congenital  and  acquired  characters, 
the  latter  may  nevertheless,  sometimes  and  in  some 
degree,  be  inherited,  however  much  difficulty  we  may 
experience  in  observing  these  lesser  phenomena  in 
presence  of  the  greater.  The  Weismannian  hypo- 
thesis of  absolute  continuity  is  one  thing,  while  the 
observed  fact  of  at  least  a  high  relative  degree  of 
continuity  is  quite  another  thing.  And  it  is  neces- 
sary to  be  emphatic  on  this  point,  since  some  of  the 
reviewers  of  my  Examittation  of  Weismannism  con- 
found these  two  things.  Being  apparently  under  the 
impression  that  it  was  reserved  for  Weismann  to 
perceive  the  fact  of  there  being  a  great  difference 
between  the  heritability  of  congenital  and  acquired 
characters,  they  deem  it  inconsistent  in  me  to 
acknowledge   this    fact    while    at    the    same    time 


m 


Characters f  Hereditary  and  Acquired.  135 

questioning  the  hypothetical  basis  of  his  funda- 
mental postulate  touching  the  absolute  continuity  of 
germ-plasm.  It  is  one  merit  of  Galton  s  theory,  as 
against  Weismann's,  that  it  does  not  dogmatically 
exclude  the  possible  interruption  of  continuity  on 
some  occasions  and  in  some  degree.  Herein,  indeed, 
would  seem  to  lie  the  central  core  of  the  whole 
question  in  dispute.  For  it  is  certain  and  has  long 
been  known  that  individually  acquired  characters 
are  at  all  events  much  less  heritable  than  are  long- 
inherited  or  congenital  ones.  But  Lamarckian  theory 
supposes  that  congenital  characters  were  in  some 
cases  originally  acquired,  and  that  what  are  now 
blastogenetic  characters  were  in  some  cases  at  first 
somatogenetic  and  have  become  blastogenetic  only 
in  virtue  of  sufficiently  long  inheritance.  Since 
Darwin's  time,  however,  evolutionists  (even  of  the 
so-called  Lamarckian  type)  have  supposed  that 
natural  selection  greatly  assists  this  process  of  deter- 
mining which  somatogenetic  characters  shall  become 
congenital  or  blastogenetic.  Hence  all  schools  of 
evolutionists  are,  and  have  long  been,  agreed  h\ 
regarding  the  continuity  principle  as  true  in  the  main. 
No  evolutionist  would  at  any  time  have  propounded 
the  view  that  one  generation  depends  for  all  its 
characters  on  those  acquired  by  its  immediate  ances- 
tors, for  this  would  merely  be  to  unsay  the  theory  of 
Evolution  itself,  as  well  as  to  deny  the  patent  facts 
of  heredity  as  shown,  for  example,  in  atavism.  At 
most  only  some  fraction  of  a  per  cent,  could  be 
supposed  to  do  so.  But  Weismann's  contention  is 
that  this  principle  is  not  only  true  in  the  main,  but 
absolutely  true ;  so  that  natural  selection  becomes  all 


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136        Darwiriy  and  after  Darwin, 


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in  all  or  not  at  a^l.  Unless  Weismannism  be  regarded 
as  this  doctrine  of  absolutism  it  permits  no  basis  for 
his  attempted  theory  of  evolution. 

And,  whatever  may  be  said  to  the  contrary  by  the 
more  enthusiastic  followers  of  Prof.  Weismann,  I  must 
insist  that  there  is  the  widest  possible  difference 
between  the  truly  scientific  question  of  fact  which  is 
assumed  by  Weismann  as  answered  (the  base-line  of 
the  diagram  on  p.  43),  and  the  elaborate  structure 
of  deductive  reasoning  which  he  has  reared  on  this 
assumption  (the  Y-like  structure).  Even  if  the 
assumption  should  ever  admit  of  inductive  proof,  the 
almost  bewildering  edifice  of  deductive  reasoning 
which  he  has  built  upon  it  would  still  appear  to  me  to 
present  extremely  little  value  of  a  scientific  kind.  In- 
teresting though  it  may  be  as  a  monument  of  ingenious 
speculation  hitherto  unique  in  the  history  of  science, 
the  mere  flimsiness  of  its  material  must  always  pre- 
vent its  far-reaching  conclusions  from  being  worthy 
of  serious  attention  from  a  biological  point  of  view. 
But  having  already  attempted  to  show  fully  in  my 
Examination  this  great  distinction  between  the 
scientific  importance  of  the  question  which  lies  at  the 
base  of  "  Weismannism,"  and  that  of  the  system  which 
he  has  constructed  on  his  assumed  answer  thereto, 
I  need  not  now  say  anything  further  with  regard  to  it. 

Again,  on  the  present  occasion  and  in  this  connexion 
I  should  like  to  dissipate  a  misunderstanding  into 
which  some  of  the  reviewers  of  the  work  just  men- 
tioned have  fallen.  They  appear  to  have  concluded 
that  because  I  have  criticized  unfavourably  a  con- 
siderable number  of  Weismann's  theories,  I  have 
shown    myself  hostile  to  his  entire   system.     Such, 


J 


h 


' 


CharaderSy  Hereditary  ana  Acquired.  137 

however,  is  by  no  means  the  case ;  and  the  mis- 
understanding can  only  be  accounted  for  by  sup- 
posing that  the  strongly  partisan  spirit  which  these 
critics  display  on  the  side  ot"  neo-Darwinism  has 
rendered  them  incapable  of  appreciating  any  attempt 
at  impartial — or  even  so  much  as  independent — 
criticism.  At  all  events,  it  is  a  matter  of  fact  that 
throughout  the  work  in  question  I  have  been  par- 
ticularly careful  to  avoid  this  misunderstanding  as  to 
my  own  position.  Over  and  over  again  it  is  there 
stated  that,  far  from  having  any  objection  to  the 
principle  of  "  Continuity  "  as  represented  in  the  base- 
line of  the  above  diagram,  I  have  been  convinced 
of  its  truth  ever  since  reading  Mr.  Galton's  Theory 
of  Heredity  in  1875.  All  the  "hard  words  '  which 
I  have  written  against  Weismann's  system  of  theories 
have  reference  to  those  parts  of  it  which  go  to  con- 
stitute the  Y-like  structure  of  the  diagram. 

It  is,  however,  desirable  to  recur  to  another  point, 
and  one  which  I  hope  will  be  borne  in  mind  through- 
out the  following  discussion.  It  has  already  been 
stated,  a  few  pages  back,  that  the  doctrine  of  con- 
tinuity admits  of  being  held  in  two  very  different 
significations.  It  may  be  held  as  absolute,  or  as 
relative.  In  the  former  case  we  have  the  Weis- 
mannian  doctrine  of  germ-plasm  :  the  substance  of 
heredity  is  taken  to  be  a  substance  per  se,  which 
has  always  occupied  a  separate  '•  sphere  "  of  its  own, 
without  any  contact  with  that  of  somatoplasm  further 
than  is  required  for  its  lodgement  and  nutrition ; 
hence  it  can  never  have  been  in  any  degree  modi- 
fied as  to  its  hereditary  qualities  by  use- inheritance 
or  any  other  kind  of  somatogenetic  change ;   it  has 


'  'Hi 


I 


138        Darwin^  and  after  Darwin, 


I,  > 

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If 


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been  absolutely  continuous  "since  the  first  origin  of 
life."  On  the  other  hand,  the  doctrine  of  continuity 
may  be  held  in  tne  widely  different  sense  in  which 
it  has  been  presented  by  Galton's  theory  of  Stirp. 
Here  the  doctrine  is,  that  while  for  the  most  part 
the  phenomena  of  heredity  are  due  to  the  continuity 
of  the  substance  of  heredity  through  numberless 
generations,  this  substance  ("  Stirp  ")  is  nevertheless 
not  absolutely  continuous,  but  may  admit,  in  small 
though  cumulative  degrees,  of  modification  by  use- 
inheritance  and  other  factors  of  the  Lamarckian  kind. 
Now  this  all- important  distinction  between  these  two 
theories  of  continuity  has  been  fully  explained  and 
thoroughly  discussed  in  my  lixaminatiofi ;  therefore 
I  will  not  here  repeat  myself  further  than  to  make 
the  following  remarks. 

The  Weismannian  doctrine  of  continuity  as  abso- 
lute (base-line  of  the  diagram)  is  necessary  for  the 
vast  edifice  of  theories  which  he  has  raised  upon  it 
(the  Y),  first  as  to  the  minute  nature  and  exact 
composition  of  the  substance  of  heredity  itself 
("  Germ-plasm  "),  nej:t  as  to  the  precise  mechanism 
of  its  action  in  producing  the  visible  phenomena  of 
heredity,  variation,  and  all  allied  phenomena,  and, 
lastly,  the  elaborate  and  ever-changing  theory  of 
organic  evolution  which  is  either  founded  on  or 
interwoven  with  this  vast  system  of  hypothetic 
speculation.  Galton's  doctrine  of  continuity,  on 
the  other  hand,  is  a  "  Theory  of  Heredity,"  and 
a  theory  of  heredity  alone.  It  does  not  meddle 
with  any  other  matters  whatsoever,  and  rigidly 
avoids  all  speculation  further  than  is  necessary  for 
the  bare  statement  and    inductive  support   of   the 


Characters^  Hereditary  and  Acquired.  139 


doctrine  in  question.  Hence,  it  would  appear  that 
this,  the  only  important  respect  wherein  the  doc- 
trine of  continuity  as  held  by  Galton  differs  from 
the  doctrine  as  held  by  Wcismann,  arises  from  the 
necessity  under  which  the  latter  finds  himself  of 
postulating  absolute  continuity  as  a  logical  basis 
for  his  deductive  theory  of  the  precise  mechanism 
of  heredity  on  the  one  iiand,  and  of  his  similarly 
deductive  theory  of  evolution  on  the  other.  So  far 
as  the  doctrine  of  continuity  is  itself  concerned 
(i.e.  the  question  of  the  inheritance  of  acquired 
characters),  there  is  certainly  no  more  inductive 
reason  for  supposing  the  continuity  absolute  "  since 
the  first  origin  of  life,"  than  there  is  for  supposing 
it  to  be  more  or  le.ss  susceptible  of  interruption  by 
the  Lamarckian  factors.  In  other  words,  but  for 
the  sake  of  constructing  a  speculative  foundation 
for  the  support  of  his  further  theories  as  to  "  the 
architecture  of  germ-plasm "  and  the  factors  of 
organic  evvilution.  there  is  no  reason  why  Weismann 
should  maintain  the  absolute  separation  of  the 
"sphere"  of  germ-plasm  from  that  of  somatoplasm. 
On  the  contrary,  he  has  no  reason  for  concluding 
against  even  a  considerable  and  a  frequent  amount 
of  cutting,  or  overlapping,  on  the  part  of  these  two 
spheres. 

But  although  this  seems  to  me  sufficiently  obvious, 
as  I  have  shown  at  greater  length  in  the  Examination 
of  Weismannism,  it  must  not  be  understood  that 
I  hold  that  there  is  room  for  any  large  amount  of 
such  overlapping.  On  the  contrary,  it  appears  to  me 
as  certain  as  anything  can  well  be  that  the  amount 
of  such  overlapping  from  one  generation  to  another, 


"•1 


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'5 


I  *i 


140         Darwin,  and  after  Darwin, 


f 


«      1. 


'.  ^> 


if  it  ever  occur  at  all,  must  be  exceedingly  small, 
so  that,  if  we  have  regard  to  only  a  few  sequent 
generations,  the  effects  of  use-inheritance,  and  La- 
marckian  factors  are,  at  all  events  as  a  rule, 
demonstrably  imperceptible.  But  this  fact  does  not 
constitute  any  evidence — as  Weismann  and  his 
followers  seem  to  suppose — against  a  possibly  im- 
portant influence  being  exercised  by  the  Lamarckian 
f-ctors,  in  the  way  of  gradual  increments  through 
a  long  series  of  generations.  It  has  long  been  well 
known  that  acquired  characters  are  at  best  far  less 
fully  and  far  less  certainly  inherited  than  are  con- 
genital ones.  And  this  fact  is  of  itself  sufficient 
to  prove  the  doctrine  of  continuity  to  the  extent 
that  even  the  Lamarckian  is  rationally  bound  to 
concede.  But  the  fact  yields  no  proof — scarcely 
indeed  so  much  as  a  presumption — in  favour  of  the 
doctrine  of  continuity  as  absolute.  For  it  is  uri- 
ciently  obvious  that  the  adaptive  work  of  heredity 
could  not  be  carried  on  at  all  if  there  had  to  be 
a  discontinuity  in  the  substance  of  heredity  at  every 
generation,  or  even  after  any  very  large  number  of 
generations. 

Little  more  need  be  said  concerning  the  argu- 
ments which  fall  under  the  headings  A  and  B.  The 
Indirect  evidence  is  considered  in  Appendix  I  of  the 
Examination  of  Weismannism ;  while  the  Direct 
evidence  is  considered  in  the  text  of  that  work  in 
treating  of  Professor  Weismann's  researches  on  the 
Hydromedusae  (pp.  71-76). 

The  facts  of  karyokinesis  are  generally  claimed 
by  the  school  of  Weismann  as  making  exclusively 
in    favour    of    continuity   as    absolute.     But    this   is 


I! 


Characters^  Hereditary  and  Acquired.  141 

a  partisan  view  to  take.  In  any  impartial  survey 
it  should  be  seen  that  while  the  facts  are  fairly 
interpretable  on  Wcismann's  theory,  they  are  by 
no  means  proof  thereof.  For  any  other  theory  of 
Heredity  must  suppose  the  material  of  heredity  to 
be  of  a  kind  more  or  less  specialized,  and  the 
mechanism  of  heredity  extremely  precise  and  well 
ordered.  And  this  is  all  that  the  facts  of  karyo- 
kinesis  prove.  Granting  that  they  prove  continuity, 
they  cannot  be  held  to  prove  that  continuity  to 
be  absolute.  In  other  words,  the  facts  are  by  no 
means  incompatible  with  even  a  large  amount  of 
commerce  between  germ-plasm  and  somato-plasm,  or 
a  frequent  transmission  of  acquired  characters. 

Again,  Weismann's  theory,  that  the  somatic  and 
the  germ-plasm  determinants  may  be  similarly  and 
simultaneously  modified  by  external  conditions  may 
be  extended  much  further  than  he  has  used  it 
himself,  so  as  to  exclude,  or  at  any  rate  invalidate, 
all  evidence  in  favour  of  Lamarckianism,  other  than 
the  inheritance  of  the  effects  of  use  and  disuse.  All 
evidence  from  apparently  inherited  effects  produced 
by  change  of  external  conditions  is  thus  virtually 
put  out  of  court,  leaving  only  evidence  from  the 
apparently  inherited  effects  of  functionally  produced 
modifications.  And  this  line  of  evidence  is  invalidated 
by  Panmixia.  Hence  there  remain  only  the  arguments 
from  selective  value  and  co-adaptation.  Weismann 
meets  these  by  adducing  the  case  of  neuter  insects, 
which  have  been  already  considered  at  sufficient 
length. 


13 


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15' 


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^ 


14a         Darwin,  and  after  Darwin, 


(C.) 

Experimental  Evidence  as  to  the  Non-inheritance 
of  Acquired  Characters, 

Let  us  now  proceed  to  the  experimental  evidence 
which  has  been  adduced  on  the  side  of  Weismannism. 

Taking  this  evidence  in  order  of  date,  we  have 
first  to  mention  that  on  which  the  school  of 
Weismann  has  hitherto  been  satisfied  almost  ex- 
clusively to  rely.  This  is  the  line  of  negative 
evidence,  or  the  seeming  absence  of  any  experimental 
demonstration  of  the  inheritance  of  acquired  char- 
acters. This  kind  uf  evidence,  however,  presents 
much  less  cof^ency  than  is  usually  supposed.  And 
it  has  been  shown  in  the  last  chapter  that  the 
amount  of  experimental  evidence  in  favour  of  the 
transmission  of  acquired  characters  is  more  con- 
siderable than  the  school  of  Weismann  seems  to  be 
aware — especially  in  the  vegetable  kingdom.  I  do 
not  think  that  this  negative  line  of  evidence  presents 
much  weight :  and,  to  show  that  I  am  not  biassed 
in  forming  this  judgement,  I  may  here  state  that  few 
have  more  reason  than  myself  for  appreciating  the 
weight  of  such  evidence.  For,  as  already  stated, 
when  first  led  to  doubt  the  Lamarckian  factors,  now 
more  than  twenty  years  igo,  I  undertook  a  research 
upon  the  whole  question — only  a  part  of  which  was 
devoted  to  testing  the  particular  case  of  Brown- 
Sdquard's  statements,  with  the  result  recorded  in  the 
preceding  chapter.  As  this  research  yielded  negative 
results  in  all  its  divisions— and,  not  only  m  the  matter 
of  Brown-S^quard's  statements — I  have  not  hitherto 


Characters^  Hereditary  and  Acquired.  143 


published  a  word  upon  the  subject.  But  it  now 
seems  worth  while  to  do  so,  and  for  the  following 
reasons. 

First,  as  just  observed,  a  brief  account  of  my  old 
experiences  in  this  field  will  serve  to  show  what  good 
reason  I  have  for  feeling  the  weight  of  such  negative 
evidence  in  favour  of  Continuity  as  arises  from  failure 
to  produce  any  good  experimental  evidence  to  the 
contrary.  In  the  second  place,  now  that  the  question 
has  become  one  of  world-wide  interest,  it  would  seem 
that  even  negative  results  deserve  to  be  published 
for  whatever  they  may  be  worth  on  the  side  of  Nco- 
Darwinism.  Lastly,  in  the  third  place,  althouiijh  the 
research  yielded  negative  results  in  my  hands,  it  is 
perhaps  not  undesirable  to  state  the  nature  of  It, 
if  only  to  furnish  suggestions  to  other  physiologists, 
in  whose  hands  the  experiments — esi)ecially  in  these 
days  of  antiseptics — may  lead  to  a  ditferent  termina- 
tion. Altogether  I  made  thousands  of  experin.v-nts 
in  graft-hydridization  (comprising  bines,  bulbs  of 
various  kinds,  buds,  and  tubers) ;  but  with  uniformly 
negative  results.  With  animals  I  tried  a  number  of 
experiments  in  grafting  characteri.stic  congenital  tissues 
from  one  variety  on  another — such  as  the  combs  of 
Spanish  cocks  upon  the  heads  of  Hamburgs ;  also, 
in  mice  and  rats,  the  grafting  together  of  different 
varieties ;  and,  in  rabbits  and  bitches,  the  transplant- 
ation of  ovaries  of  newly-born  individuals  belonging 
to  different  well-marked  breeds.  This  latter  experi- 
ment seems  to  be  one  which,  if  successfully  performed 
(so  that  the  transplanted  ovaries  would  form  their 
attachment  in  a  young  bitch  puppy  and  subsequently 
yield  progeny  to  a  dog  of  the  same  breed  as  herself) 


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would  furnish  a  crucial  test  as  to  the  inheritance  or 
non-inheritance  of  acquired  characters.  Therefore 
I  devoted  to  it  a  large  share  of  my  attention,  and 
tried  the  experiment  in  several  different  ways.  But 
I  was  never  able  to  get  the  foreign  ovary — or  even  any 
portion  thereof — to  graft.  Eventually  the  passing  of 
the  Vivisection  Act  caused  me  to  abandon  the  whole 
research  as  far  as  animals  were  concerned — a  research, 
indeed,  of  which  I  had  become  heartily  tired,  since  in 
no  one  instance  did  I  obtain  any  adhesion.  During 
the  last  few  years,  however,  I  have  returned  to  these 
experiments  under  a  licence,  and  with  antiseptic 
precautions,  but  with  a  similar  want  of  success. 
Perhaps  this  prolonged  and  uniformly  fruitless  expe- 
rience may  now  have  the  eftiect  of  saving  the  time  of 
other  physiologists,  by  warning  them  off  the  roads 
where  there  seems  to  be  no  thoroughfare.  On  the 
other  hand,  it  may  possibly  lead  some  one  else  to 
try  some  variation  in  the  method,  or  in  the  material, 
which  has  not  occurred  to  me.  In  particular,  I  am 
not  without  hope  that  the  transplantation  of  ovaries 
in  very  young  animals  may  eventually  prove  to  be 
physiologically  possible;  and,  if  so,  that  the  whole 
issue  as  between  the  rival  theories  of  heredity  will 
be  settled  by  the  result  of  a  single  experiment. 
Possibly  some  of  the  invertebrata  will  be  found  to 
furnish  the  suitable  material,  although  I  have  been 
unable  to  think  of  any  of  these  which  present 
sufficiently  well-marked  varieties  for  the  purpose. 
But,  pending  the  successful  accomplishment  of  this 
particular  experiment  in  the  grafting  of  any  animal 
tissue,  I  think  it  would  be  clearly  unjustifiable  to 
conclude    against  the    Lamarckian    factors   on    the 


vjr 


Character Sy  Hereditary  and  Acquired.     145 

ground  of  any  other  experiments  yielding  negative 
results  in  but  one  generation  or  even  in  a  large 
number  of  sequent  generations. 

For  instance,  the  latter  consideration  applies  to  the 
negative  results  of  Mr.  Francis  Galton's  celebrated 
Experiments  in  Pangenesis  \  These  consisted  in 
transfusing  the  blood  of  one  variety  of  rabbit  into 
the  veins  of  both  sexes  of  another,  and  then  allowing 
the  latter  to  breed  together :  in  no  case  was  there  any 
appearance  in  the  progeny  of  characters  distinctive 
of  the  variety  from  which  the  transfused  blood  was 
derived.  But,  as  Mr.  Galton  himself  subsequently 
allov/ed,  this  negative  result  constitutes  no  disproof 
of  pangenesis,  seeing  that  only  a  portion  of  the 
parents'  blood  was  replaced  ;  that  this  portion,  even 
if  charged  with  '*gemmules,"  would  contain  but 
a  very  small  number  of  these  hypothetical  bodies, 
compared  with  those  contained  in  all  the  tissues  of 
the  parents  ;  and  that  even  this  small  proportional 
number  would  presumably  be  soon  overwhelmed  by 
those  contained  in  blood  newly-made  by  the  parents. 
Nevertheless  the  experiment  was  unquestionably 
worth  trying,  on  the  chance  of  its  yielding  a  positive 
result ;  for,  in  this  event,  the  question  at  issue 
would  have  been  closed.  Accordingly  I  repeated 
these  experiments  (with  the  kind  help  of  Professor 
Schiifer),  but  with  slight  differences  in  the  method, 
designed  to  give  pangenesis  a  better  chance,  so  to 
speak. 

Thus  I  chose  wild  rabbits  to  supply  the  blood, 
and  Himalayan  to  receive  it — the  former  being  the 
ancestral    type   (and    therefore    giving   reversion   an 

*  Proc.  R.  S.  1871. 

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146        DarwiUy  and  after  Darwin, 


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Opportunity  of  coming  into  play),  while  the  latter, 
although  a  product  of  domestication,  is  a  remarkably 
constant  variety,  and  one  which  differs  very  much 
in  size  and  colour  from  the  parent  species.  Again, 
instead  of  a  single  transfusion,  there  were  several 
transfusions  performed  at  different  times.  Moreover, 
we  did  not  merely  allow  the  blood  of  one  rabbit 
to  flow  into  the  veins  of  the  other  (whereby  little 
more  than  half  the  blood  could  be  substituted) ; 
but  sacrificed  three  wild  rabbits  for  refilling  the 
vascular  system  of  each  tame  one  on  each  occasion. 
Even,  as  thus  improved,  however,  the  experiment 
yielded  only  negative  results,  which,  therefore,  we 
never  published. 

Subsequently  I  found  that  all  this  labour,  both 
on  Mr.  Galton's  part  and  our  own,  was  simply 
thrown  away — not  because  it  yielded  only  negative 
results,  but  because  it  did  not  serve  as  a  crucial 
experiment  at  all.  The  material  chosen  was  un- 
serviceable for  the  purpose,  inasmuch  as  rabbits, 
even  when  crossed  in  the  ordinary  way,  never  throw 
intermediate  characters.  Needless  to  say,  had  I  been 
aware  of  this  fact  before,  I  should  never  have  re- 
peated Mr.  Galton's  experiments  —nor,  indeed,  would 
he  have  originally  performed  them  had  he  been  aware 
of  it.  So  all  this  work  goes  for  nothing.  The  research 
must  begin  all  over  again  with  some  other  animals, 
the  varieties  of  which  when  crossed  do  throw  inter- 
mediate characters. 

Therefore  I  have  this  year  made  arrangements 
for  again  repeating  the  experiments  in  question — 
only,  instead  of  rabbits,  using  well-marked  varieties 
of  dogs.     A  renewed  attack  of  illness,  however,  has 


Characters f  Hereditary  and  Acquired.  147 

necessitated  the  surrender  of  this  research  to  other 
hands,  with  a  consequent  delay  in  its  commencement. 
My  ignorance  of  the  unfortunate  peculiarity  dis- 
played by  rabbits  in  not  throwing  intermediate 
characters  has  led  to  a  further  waste  of  time  in 
another  line  of  experiment.  On  finding  that  mam- 
malian ovaries  did  not  admit  of  being  grafted,  it 
seemed  to  me  that  the  next  best  thing  to  try  would  be 
the  transplantation  of  fertilized  ova  from  one  variety 
to  another,  for  the  purpose  of  ascertaining  whether, 
if  a  parturition  should  take  place  under  such  circum- 
stances, gestation  by  the  uterine  mother  would  affect 
the  characters  of  the  ovum  derived  from  the  ovarian 
mother — she,  of  course,  having  been  fertilized  by  a 
male  of  her  own  variety.  Of  course  it  was  necessary 
that  both  the  mothers  should  be  in  season  at  about  the 
same  time,  and  therefore  I  again  chose  rabbits,  seeing 
that  in  the  breeding  season  they  are  virtually  in  a 
chronic  state  of  "  heat."  I  selected  Himalayans  and 
Belgian  hares,  because  they  are  well-marked  varieties, 
breed  true,  and  in  respect  of  colour  are  very  different 
from  one  another.  It  so  happened  that  while  I  was 
at  work  upon  this  experiment,  it  was  also  being  tried, 
unknown  to  me,  by  Messrs.  Heape  and  Buckley  who, 
curiously  enough,  employed  exactly  the  same  material. 
They  were  the  first  to  obtain  a  successful  result. 
Two  fertilized  ova  of  the  Angora  breed  having  been 
introduced  into  the  fallopian  tube  of  a  Belgian  hare, 
developed  there  in  due  course,  and  gave  rise  to  two 
Angora  rabbits  in  no  way  modified  by  their  Belgian 
hare  gestation  ^ 

'  Proc.  R.  S.  1890,  vol.  xlviii.  p.  457.     It  should  be  stated  that  the 
authors  do  uot  here  concern  themselves  with  any  theory  of  heredity. 

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148         Darwt'n,  and  after  Darwin, 

But,  interesting  and  suggestive  as  this  experinment 
is  in  other  connexions,  it  is  clearly  without  sig- 
nificance in  the  present  one,  for  the  reason  already 
stated.  It  will  have  to  be  tried  on  well-marked  varieties 
of  other  species  of  animals,  which  are  known  to  throw 
intermediate  characters.  Even,  however,  if  it  should 
then  yield  a  similarly  negative  result,  the  fact  would 
not  tell  against  the  inheritance  of  acquired  characters; 
seeing  that  an  ovum  by  the  time  it  is  ripe  is  a  finished 
product,  and  therefore  not  to  be  expected,  on  any 
thecy  of  heredity,  to  be  influenced  as  to  its  hereditary 
potentialities  by  the  mere  process  of  gestation.  On 
the  other  hand,  if  it  should  prove  that  it  does  admit 
of  being  thus  affected,  so  that  against  all  reasonable 
expectation  the  young  animal  presents  any  of  the 
hereditary  characters  of  its  uterine  mother,  the 
fact  would  terminate  the  question  of  the  transmission 
of  acquired  characters — and  this  quite  as  effectually 
as  would  a  similarly  positive  result  in  the  case  of 
progeny  from  an  ingrafted  ovary  of  a  different 
variety.  In  point  of  fact,  the  only  difference  between 
the  two  cases  would  be,  that  in  the  former  it  might 
prove  possible  to  close  the  question  on  the  side  of 
Lamarckianism,  in  the  latter  it  would  certainly 
close  the  question,  either  on  this  side  or  on  the 
opposite  as  the  event  would  determine. 

The  only  additional  fact  that  has  hitherto  been 
published  by  the  school  of  Weismann  is  the  result 
of  Weismann's  own  experiment  in  cutting  off  the 
tails  of  mice  through  successive  generations.  But 
this  experiment  does  not  bear  upon  any  question 
that  is  in  debate ;  for  no  one  who  is  acquainted 
with  the  literature  of  the  subject  would  have  expected 


Characters  J  Hereditary  and  Acquired.   149 

any  positive  result  to  follow  from  such  a  line  of 
inquiry.  As  shown  further  back  in  the  text,  Darwin 
had  carefully  considered  the  case  of  mutilations, 
and  explained  that  their  non-transmissibility  con- 
stitutes no  valid  objection  to  his  theory  of  pangenesis. 
Furthermore,  it  may  now  be  added,  he  expressly 
alluded  in  this  connexion  to  the  cutting  off  of  tails, 
as  practised  by  horse-breeders  and  dog-fanciers, 
"through  a  number  of  generations,  without  any 
inherited  effect."  He  also  alluded  to  the  still  better 
evidence  which  is  furnished  by  the  practice  of  cir- 
cumcision. Therefore  it  is  difficult  to  understand 
the  object  of  Weismann's  experiment.  Yet,  other 
than  the  result  of  this  experiment,  no  new  fact 
bearing  on  the  question  at  issue  has  been  even  so 
much  as  alleged. 


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CHAPTER  VI. 

Characters  as  Hereditary  and  Acquired 

(conclusion  ^). 

In  the  foregoing  chapters  I  have  endeavoured 
to  be,  before  all  things,  impartial ;  and  if  it  seems 
that  I  have  been  arguing  chiefly  in  favour  of  the 
Lamarckian  principles,  this  has  been  because  the 
only  way  of  examining  the  question  is  to  consider 
what  has  to  be  said  on  the  affirmative  side,  and 
then  to  see  what  the  negative  side  can  say  in 
reply.  Before  we  are  entitled  to  discard  the  Lamarck- 
ian factors  in  toto^  we  must  be  able  to  destroy 
all  evidence  of  their  action.  This,  indeed,  is  what 
the  ultra- Darwinians  profess  to  have  done.  But 
is  not  their  profession  premature?  Is  it  not  evident 
that  they  have  not  sufficiently  considered  certain 
general  facts  of  nature,  or  certain  particular  results 
of  experiment,  which  at  all  events  appear  inex- 
plicable by  the  theory  of  natural  selection  alone? 
In  any  case  the  present  discussion  has  been  devoted 
mainly  to  indicating  such  general  facts  and  par- 
ticular results.     If  I  have  fallen  into  errors,  either 


[^  Su  note  appended  to  Preface.    C.  LI.  M.] 


f 


Characters f  Hereditary  and  Acquired.  151 

of  statement  or  of  reasoning,  it  is  for  the  ultra- 
Darwinians  to  correct  them ;  but  it  may  be  well  to 
remark  beforehand,  that  any  criticism  of  a  merely 
general  kind  touching  the  comparative  paucity  of  the 
facts  thus  adduced  in  favour  of  Lamarck ian  doctrine, 
will  not  stand  as  a  valid  criticism.  For,  as  we 
have  seen  in  the  opening  part  of  the  discussion, 
even  if  use-inheritance  and  direct  action  of  the 
environment  have  been  of  high  importance  as  factors 
of  organic  evolution,  it  must  be  in  almost  all  cases 
impossible  to  dissociate  their  influence  from  that 
of  natural  selection — at  any  rate  where  plants  and 
animals  in  a  state  of  nature  are  concerned.  On 
the  other  hand,  experiments  expressly  devised  to 
test  the  question  have  not  hitherto  been  carried 
out.  Besides,  the  facts  and  arguments  here  adduced 
are  but  comparatively  few.  For.  unless  it  can  be 
shown  that  what  has  been  said  of  reflex  action, 
instinct,  so-called  '*  self-adaptation  "  in  plants,  &c.,  is 
wrong  in  principle,  the  facts  which  tell  in  favour 
of  Lamarckian  theory  are  absolutely  very  numerous. 
Only  when  considered  in  relation  to  cases  where 
we  are  unable  to  exclude  the  conceivable  possi- 
bility of  natural  selection  having  been  at  work,  can 
it  be  said  that  the  facts  in  question  are  not 
numerous. 

Comparatively  few,  then,  though  the  facts  may 
be  of  which  I  have  given  some  examples,  in  my 
opinion  they  are  amply  sufficient  for  the  purpose 
in  hand.  This  purpose  is  to  show  that  the  question 
which  we  are  now  considering  is  very  far  from 
being  a  closed  question ;  and,  therefore,  that  the 
school    of   Weismann    is    much    too    precipitate    in 


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152         Darwm,  and  after  Darwin. 

alleging  that  there  is  neither  any  necessity  for, 
nor  evidence  of,  the  so-called  Lamarckian  factors  ^ 
And  this  opinion,  whatever  it  may  be  worth,  is 
at  all  events  both  deliberate  and  impartial.  As 
one  '^f  the  '^rst  to  doubt  the  transmission  of  acquired 
chai.  "  e  and  as  one  who  has  spent  many  years 
in  e>.;  .5;,i!i5i  "\tal  inquiries  upon  the  subject,  any 
bias  th»t  I  '  "xy  have  is  assuredly  against  the 
Lamarckian  principles — seeing  that  nearly  all  my 
experiments  have  yielded  negative  results.  It  was 
Darwin  himself  who  checked  this  bias.  But  if  the 
ultra-Darwinians  of  the  last  ten  years  had  succeeded 
in  showing  that  Darwin  was  mistaken.  I  should  be 
extremely  glad  to  fall  into  line  with  them.  As 
already  shown,  however,  they  have  in  no  way  affected 
this  question  as  it  was  left  by  Galton  in  1875.  And 
if  it  be  supposed  a  matter  of  but  little  importance 
whether  we  agree  with  Galton  in  largely  diminish- 
ing the  comparative  potency  of  the  Lamarckian 
principles,  or  whether  we  agree  with  Weismann 
in  abohshing  them  together,  it  cannot  be  too  often 
repeated  that  such  is  an  entirely  erroneous  view. 
No  matter  how  faintly  or  how  fitfully  acquired 
characters  may  be  transmitted,  in  so  far  as  they 
are  likewise  adaptive  characters,  their  transmission 
(and  therefore  their  development)  must  be  cumu- 
lative. Hence,  the  only  effect  of  attenuating  our 
estimate  of  their  intensity,  is  that  of  increasing 
our  estimate  of  their  duration — i.e.  of  the  time  over 
which    they   have   to   operate   in   order   to  produce 

*  E.g.  "The  supposed  transmission  of  this  artificially  produced 
disease  (epilepsy)  is  the  only  definite  instance  which  has  been  brought 
lorward  in  support  of  the  transniissiou  of  acquired  characters." — Essays, 
p.  328. 


ill 


Characters,  Hereditary  and  Acquired.   153 

important   results.     And,    even   so,   it   is   to   be  re- 
membered that   the   importance  of  such    results   is 
not  to  be  estimated  by  the  magnitude  of  modification. 
Far   more   is   it   to   be  estimated   by  the   character 
of   modification    as    adaptive.     For    if    functionally 
produced  changes,  and  changes  produced  in  adaptive 
response  to  the  environment,  are   ever   transmitted 
in    a   cumulative    manner,    a   time    must   sooner  or 
later   arrive  when  they  will  reac'    a  selective  value 
in  the  struggle  for  existence — whon     )f  course,  they 
will    be    rapidly    augmented    \-y    hl  ural    selection. 
Thus,  if  in   any  degree  oper.  ti .  e  at  all,  the  great 
function  of  these  principles  must  L«j  that  of  supplying 
to  natural  selection  those  inci^     ^  1  stages  of  adaptive 
modifications    in    all    cases    where,    but    for    their 
agency,  there  would  have  been  nothing  of  the  kind 
to    select.     Themselves    in    no    way    dependent   on 
adaptive    modifications    having    already    attained    a 
selective    value,    these    Lamarckian    principles    are 
(under  the  Darwinian  theory)  direct  causes  of  deter- 
minate variation   in    adaptive    lines ;    and   variation 
in  those  lines   being  cumulative,  the  result  is  that 
natural  selection  is  in  large  part  presented  with  the 
raw  material  of  its  manufacture — special  material  of 
the  particular  kinds  required,  as  distinguished  from 
promiscuous   material  of  all  kinds.     And  the  more 
complex  the  manufacture  the  more   important  will 
be   the  work  of  this  subordinate  factory.     We  can 
well    imagine  how  the  shell  of  a  nut,  for  instance, 
or  even  the  protective  colouring  of  an  insect,  may 
have  been  gradually  built  up  by   natural   selection 
alone.     But  just  in  proportion  as  structures  or  organs 
are  not  merely  thus  of  passive  use  (where,  of  course, 


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154         Darwin,  and  after  Darwin, 


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the  Lamarckian  principles  cannot  obtain),  but  require 
to  be  actively  used,  in  that  proportion  does  it  become 
difficult  to  understand  the  incipient  construction 
of  them  by  natural  selection  alone.  Therefore,  in 
many  such  cases,  if  the  incipient  construction  is 
not  to  be  explained  by  the  Lamarckian  principles, 
it  is  difficult  to  see  how  it  is  to  be  explained  at  all. 

Furthermore,  since  the  question  as  to  the  trans- 
mission of  acquired  characters  stands  now  exactly 
as  it  did  after  the  publication  of  Mr.  Galton's 
Theory  of  Heredity  twenty  years  ago,  it  would  seem 
that  our  judgement  with  regard  to  it  should  remain 
exactly  what  it  was  then.  Although  we  must 
"  out-Darwin  Darwin "  to  the  extent  of  holding 
that  he  assigned  too  large  a  measure  of  intensity 
to  the  Lamarckian  factors,  no  sufficient  reason 
has  been  shown  for  denying  the  existence  of 
these  factors  in  toto;  while,  on  the  other  hand, 
there  are  certain  general  considerations,  and  certain 
particular  facts,  which  appear  to  render  it  prob- 
able that  they  have  played  a  highly  important 
part  in  the  process  of  organic  evolution  as  a  whole. 
At  the  same  time,  and  in  the  present  state  of 
our  information,  this  judgement  must  be  deemed 
provisional,  or  liable  eventually  to  be  overturned 
by  experimental  proof  of  the  non-inheritance  of 
acquired  characters.  But,  even  if  this  should  ever 
be  finally  accomplished,  the  question  would  still 
remain  whether  the  principle  of  natural  selection 
alone  is  capable  of  explaining  all  the  facts  of  adap- 
tation ;  and,  for  my  own  part,  I  should  then  be 
disposed  to  believe  that  there  must  be  some  other, 
though    hitherto    undiscovered,    principle    at    work, 


Characters f  Hereditary  and  Acquired.   155 

which  co-operates  with  natural  selection,  by  playing 
the  subordinate  r6)e  which  was  assigned  by  Darwin 
to  the  principles  of  Lamarck. 

Finally,  let  it  be  noted  that  no  part  of  the  fore- 
going argument  is  to  be  regarded  as  directed  against 
\}c\Q principle  of  what  Professor  Weismann  calls  "con* 
tinuity."  On  the  contrary,  it  appears  to  be  self-evident 
that  this  principle  must  be  accepted  in  some  degree 
or  another  by  every  one,  whether  Darwinians,  Neo- 
Darwinians,  Lamarckians,  Neo-Lamarckians,  or  even 
the  advocates  of  special  creation.  Yet,  to  hear  or 
to  read  some  of  the  followers  of  Weismann,  one 
can  only  conclude  that,  prior  to  his  publications  on 
the  subject,  they  had  never  thought  about  it  at  all. 
These  naturalists  appear  to  suppose  that  until  then 
the  belief  of  Darwinians  was,  that  there  could  be 
no  hereditary  "  continuity  "  between  any  one  organic 
type  and  another  (such,  for  instance,  as  between 
Ape  and  Man),  but  that  the  whole  structure  of  any 
given  generation  must  be  due  to  "gemmules" 
or  "  somato-plasm,"  derived  exclusively  from  the 
preceding  generation.  Nothing  can  show  more 
ignorance,  or  more  thoughtlessness,  with  regard  to 
the  whole  subject.  The  very  basis  of  the  general 
theory  of  evolution  is  that  there  must  always  have 
been  a  continuity  in  the  material  substance  of 
heredity  since  the  time  when  the  process  of  evolution 
began  ;  and  it  was  not  reserved  for  our  generation, 
or  even  for  our  century,  to  perceive  the  special 
nature  of  this  material  substance  in  the  case  of  sexual 
organisms.  No,  the  real  and  the  sole  question,  where 
Weismann's  theory  of  heredity  is  concerned,  is  simp]  ' 
this — Are  we  to  hold  that  this  material  substance 


Hi 

!tr 


'•Vk 


ts 


! 


'  I 


156         Darwin,  and  after  Darwin. 


r  Ml. 


4 


{,  '* 


S  S.  i 

If  :^ 

'I,  'rM 


•n^ 


i 


has  been  absolutely  continuous  "  since  the  first  origin 
of  sexual  propagation,"  always  occupying  a  separate 
"sphere"  of  its  own,  at  all  events  to  the  extent  of 
never  having  been  modified  by  the  body  substance 
in  which  it  resides  (Lamarckian  factors);  or^  are 
we  to  hold  that  this  "  germ-plasm,"  "  stirp,"  or  "  forma- 
tive-material," has  been  but  relatively  continuous, 
so  as  to  admit  of  some  amount  of  commerce 
with  body-substance,  and  therefore  to  admit  of 
acquired  characters,  when  sufficiently  long  continued 
as  such,  eventually  becoming  congenital?  If  this 
question  be  answered  in  the  latter  sense,  of  course 
the  further  question  arises  as  to  the  degree  of 
such  commerce,  or  the  time  during  which  acquired 
characters  must  continue  to  be  acquired  in  suc- 
cessive generations  before  they  can  sufficiently 
impress  themselves  on  the  substance  of  heredity 
to  become  congenital.  But  this  is  a  subordinate 
question,  and  one  which,  in  the  present  state  of 
our  information,  it  seems  to  me  almost  useless  to 
speculate  upon.  My  own  opinion  has  always  been 
the  same  as  that  of  Mr.  Galton ;  and  my  belief  is 
that  eventually  both  Weismann  and  his  followers 
will  gravitate  into  it.  It  was  in  order  to  precipitate 
this  result  as  far  as  possible  that  I  wrote  the 
Examination.  If  it  ever  should  be  accomplished, 
Professor  Weismann's  elaborate  theory  of  evolution 
will  have  had  its  bases  removed. 


SECTION   II 


UTILITY 


%  : 


^ 


*   l\ 


f 

\ 


I 


Hi 


I  3 


CHAPTER  VII. 
Characters  as  Adaptive  and  Specific. 

One  of  the  great  changes  which  has  been  wrought 
in  biological  science  by  the  Darwinian  theory  of 
natural  selection,  consists  in  its  having  furnished 
an  intelligible  explanation  of  the  phenomena  of 
adaptation.  Indeed,  in  my  opinion,  this  is  the  most 
important  function  which  this  theory  has  had  to 
perform ;  and  although  we  still  find  systematic 
zoologists  and  systemat?"  botanists  who  hold  that 
the  chief  merit  of  Darwin's  work  consists  in  its 
having  furnished  an  explanation  of  the  origin  of 
species^  a  very  little  consideration  is  enough  to 
show  that  such  an  idea  is  but  a  survival,  or  a 
vestige,  of  an  archaic  system  of  thought.  So  long 
as  species  were  regarded  as  due  to  separate  acts 
of  creation,  any  theory  which  could  explain  their 
production  by  a  process  of  natural  evolution  became 
of  such  commanding  importance  in  this  respect, 
that  we  cannot  wonder  if  in  those  days  the  principal 
function  of  Darwin's  work  was  held  to  be  what 
the  title  of  that  work— 77/^  Origin  of  Species  by 
means  of  Natural  Selection — itself  serves  to  convey. 
And,  indeed,  in  those  days  this  actually  was  the 
principal  function  of  Darwin's  work,  seeing  that  ia 


Hi 


M      i 


^1 


«: 


is 


Ma        I 


'I 

'I: 

If- 


ii 


i6o         Darwin,  and  after  Darwin. 

those  days  the  fact  of  evolution  itself,  as  distin- 
gr  shed  from  its  method,  had  to  be  proved ;  and 
that  the  whole  proof  had  to  stand  or  fall  with 
the  evidence  which  could  be  adduced  touching  the 
mutability  of  species.  Therefore,  without  question, 
Darwin  was  right  in  placing  this  issue  as  to  the 
stability  or  instability  of  species  in  the  forefront  of 
his  generalizations,  and  hence  in  constituting  it  the 
title  of  his  epoch-making  book.  But  nowadays,  when 
the  fact  of  evolution  has  been  sufficiently  established, 
one  would  suppose  it  self-evident  that  the  theory 
of  natural  selection  should  be  recognized  as  cover- 
ing a  very  much  larger  field  than  that  of  explaining 
the  origin  of  species — that  it  should  be  recognized 
as  embracing  the  whole  area  of  organic  nature  in 
respect  of  adaptations,  whetlier  these  happen  to  be 
distinctive  of  species  only,  or  of  genera,  families, 
orders,  classes,  and  sub-kingdoms.  For  it  follows 
from  the  general  fact  of  evolution  that  species  are 
merely  arbitrary  divisions,  which  present  no  deeper 
significance  from  a  philosophical  point  of  view  than 
is  presented  by  well-marked  varieties,  out  of  which 
they  are  in  all  cases  believed  to  have  arisen,  and 
from  which  it  is  often  a  matter  of  mere  individual 
taste  whether  they  shall  be  separated  by  receiving 
the  baptism  of  a  specific  name.  Yet,  although 
naturalists  are  now  unanimously  agreed  that  what 
they  classify  as  species  are  nothing  more  than 
pronounced — and  in  some  greater  or  less  degree 
permanent — varieties,  so  forcible  is  the  influence  of 
traditional  modes  of  thought,  that  many  zoologists 
and  botanists  still  continue  to  regard  the  origin  of 
species  as  a  matter  of  more  importance  than  the  origin 


.ft'  i 


Characters  as  Adaptive  and  Specific.    i6i 

of  adaptations.  Consequently,  they  continue  to  repre- 
sent the  theory  of  natural  selection  as  concerned, 
primarily,  with  explaining  the  origin  of  species, 
and  denounce  as  a  "heretic"  any  one  who  regards 
the  theory  as  primarily  a  theory  of  the  origin  and 
cumulative  development  of  adaptations — whether 
structural  or  instinctive,  and  whether  the  adaptations 
are  severally  characteristic  of  species  only  or  of 
any  of  the  higher  taxonomic  divisions.  Indeed,  these 
naturalists  appear  to  deem  it  in  some  way  a  dis- 
paragement of  the  theory  to  state  that  it  is,  primarily, 
a  theory  of  adaptations,  and  only  becomes  second- 
arily a  theory  of  species  in  those  comparatively 
insignificant  cases  where  the  adaptations  ^^appen 
to  be  distinctive  of  the  lowest  order  of  taxonomic 
division — a  view  of  the  matter  which  may  fitly 
be  compared  to  that  of  an  astronomer  who  .->hould 
define  the  nebular  hypothesis  as  a  theo<*v  of  the 
origin  of  Saturn's  rings.  It  is  indeed  a  theory  of  the 
origin  of  Saturn's  rings ;  but  only  because  it  is  a  theory 
of  the  origin  of  the  entire  solar  system,  of  which 
Saturn's  rings  form  a  part.  Similarly,  the  theory 
of  natural  selection  is  a  theory  of  the  entire  system 
of  organic  nature  in  respect  of  adaptations,  whether 
these  happen  to  be  distinctive  of  particular  species 
only,  or  are  common  to  any  number  of  species. 

Now  the  outcry  which  has  been  raised  over  this 
definition  of  the  theory  of  natural  selection  is 
a  curious  proof  of  the  opposition  which  may  be 
furnished  by  habitual  modes  of  thought  to  an  exceed- 
ingly plain  matter  of  definition.  For,  I  submit,  that 
no  one  can  deny  any  of  the  following  propositions  ; 
nor  can  it   be  denied   that  from  these   propositions 

Tl  M 


• 

M 

^« 


i4 


vy 


*fc  tl 


H( 


i62         Darwin,  and  after  Darwin. 


r. 
I.  » 


I 


U' 


Ik 


fi 


111 

'li' 


i|| 


^ 


■'i»i' 


the  foregoing  definition  of  the  theory  in  question 
follows  by  way  of  necessity.  The  propositions  are, 
first,  that  natural  selection  is  taken  to  be  the 
agency  which  is  mainly,  if  not  exclusively,  con- 
cerned in  the  evolution  of  adaptive  characters : 
secondly,  that  these  characters,  when  evolved,  are  in 
some  cases  peculiar  to  single  species  only,  while  in 
other  cases,  and  in  process  of  time,  they  become 
the  common  property  of  many  species :  thirdly,  that 
in  cases  where  they  are  peculiar  to  single  species 
only,  they  constitute  at  all  events  one  of  the  reasons 
(or  even,  as  the  ultra-Darwinians  believe,  the  only 
reason)  why  the  particular  species  presenting,  them 
have  come  to  be  species  at  all.  Now,  tliese  being 
the  propositions  on  which  we  are  all  ai^Teed,  it 
obviously  follows,  of  logical  necessity,  that  tlie  theory 
in  question  is  primarily  one  which  explains  tlie  exis- 
tence of  adaptive  characters  wherevt  '  these  occur ; 
and,  therefore,  whether  tb'^y  happen  to  be  restricted 
to  single  species,  cv  are  common  to  a  whole 
group  of  species.  Oi  couise  in  cases  where  they 
are  restricted  to  single  species,  the  theory  which 
explains  the  origin  of  these  particular  adaptations 
becomes  also  a  theory  which  explains  the  origin 
of  these  particular  species ;  seeing  that,  as  we  are 
all  agreed,  it  is  in  virtue  of  such  particular  adapta- 
tions that  such  particular  species  exist.  Yet  even 
in  these  cases  the  theory  is,  primarily,  a  theory 
of  the  adaptations  in  virtue  of  which  the  particular 
species  exists ;  for,  ex  hypothesi,  it  is  the  adaptatic»iis 
which  cond  tion  the  species,  not  the  species  the 
adaptations.  But,  as  just  observed,  adaptations  may 
be  the  common  property  of  whole  groups  of  species  ; 


Characters  as  Adaptive  and  Specific.    163 

and  thus  the  theory  of  natural  selection  becomes 
a  theory  of  the  origin  of  genera,  of  families,  of  orders, 
and  of  classes,  quite  as  much  as  it  is  a  theory  of  the 
origin  of  species.  In  other  words,  it  is  everywhere 
a  theory  of  adaptations ;  and  it  is  only  where 
the  adaptations  happen  to  be  restricted  to  single 
species  that  the  theory  therefore  and  incidentally 
becomes  also  a  theory  of  the  particular  species  which 
presents  them.  Hence  it  is  by  no  means  the  same 
proposition  to  affirm  that  the  theory  of  natural 
selection  is  a  theory  of  the  origin  of  species,  and 
that  it  is  a  theory  of  the  origin  of  adaptations,  as 
some  of  my  critics  have  reipresented  it  to  be ;  for 
these  two  things  are  by  no  means  conterminous. 
And  in  as  far  as  the  two  propositions  diftcr,  ic  is 
perfectly  obvious  that  the  latter  is  the  true  oae. 

Possibly,  however,  it  may  be  said — Assuredly  natural 
selection  is  a  theory  of  the  origin  (i.e.  cumulative 
development)  of  adaptations;  and,  no  less  assurvijdl/, 
although  species  owe  their  origin  to  such  adaptat  -uns, 
there  is  now  no  common  measure  between  these  two 
things,  seeing  that  in  numberle?  cases  the  same 
adaptations  are  the  common  proi  ty  of  numberless 
species.  But,  allowing  all  this,  we  must  still  remember 
that  in  the\v  first  beginnings  2M  thvse  adaptations  must 
have  been  distinctive  of,  or  pec  iar  to,  some  one  par- 
ticular species,  which  afterwards  gave  rise  to  a  whole 
genus,  family,  order,  or  class  of  species,  all  of  vvhich 
inherited  the  particular  adaptations  derived  from 
this  common  ancestor,  while  progressively  gaining 
additional  adaptive  characters  severally  distinctive  of 
their  subsequently  diverging  lit.  s  of  descent,  So 
that   really   all   adaptive   characters   must  originally 

M  2 


m 


%  I 
5.., 


!  I 


5;.-... 


r  ^  .> 


If"--. 


f     ! 


164         Darwifij  and  after  Darwin. 

have  been  specific  characters ;  and  therefore  there  is 
no  real  distinction  to  draw  between  natural  selection 
as  a  theory  of  species  and  as  a  theory  of  adaptations. 
Well,  if  this  objection  were  to  be  advanced,  the 
answer  would  be  obvious.  Although  it  is  true  that 
every  adaptive  character  which  is  now  common  to 
a  group  of  species  must  originally  have  been  dis- 
tinctive of  a  single  parent  species,  it  by  no  means 
follows  that  in  its  first  beginning  as  a  spe  :ific  character 
it  appeared  in  the  fully  developed  form  which  it  now 
presents  as  a  generic,  family,  ordinal,  or  yet  higher 
character.  On  the  contrary,  it  is  perfectly  certain 
that  in  the  great  majority  of  instances  such  cannot 
possibly  have  been  the  case  ;  and  the  larger  the  group 
of  species  over  which  any  particular  adaptive  character 
now  extends,  the  more  evidently  do  we  perceive  that 
this  character  must  itself  have  been  the  product  of 
a  gradual  evolution  by  natural  selection  through  an 
innumerable  succession  of  species  in  branching  lines. 
The  ving  of  a  bird,  for  example,  is  an  adaptive 
structure  which  cannot  possibly  have  ever  appeared 
suddenly  as  a  merely  specific  character :  it  must  have 
been  slowly  elaborated  through  an  incalculable  number 
of  successive  species,  as  these  branched  into  genera, 
families,  and  orders  of  the  existing  class.  So  it  is 
with  other  class  distinctions  of  an  adaptive  kind; 
and  so,  in  progressively  lessening  degrees,  is  it  with 
adaptive  characters  of  an  ordinal,  a  family,  or  a  generic 
value.  That  is  to  say,  in  all  cases  where  an  adaptive 
structure  is  common  to  any  considerable  group  of 
species,  we  meet  with  clear  evidence  that  the  stiucture 
has  been  the  product  of  evolution  through  the  ancestry 
of   those   species;    and   this    evidence    becomes   in- 


is 


Characters  as  Adaptive  and  Specific.    165 

creasingly  cogent  the  higher  the  taxonomic  vaUic 
of  the  structure.  Indeed,  it  may  be  laid  down  as 
a  general  rule,  that  the  greater  the  degree  of  adapta- 
tion the  greater  is  its  diffusion — both  as  regards 
the  number  of  species  which  present  it  now,  and 
the  number  of  extinct  species  through  which  it  has 
been  handed  down,  in  an  ever  ramifying  extension 
and  in  an  ever  improving  form.  Species,  therefore, 
may  be  likened  to  leaves :  successive  and  transient 
crops  are  necessary  for  the  gradual  building  up  of 
adaptations,  which,  like  the  woody  and  permanent 
branches,  grow  continuously  in  importance  and 
efficiency  through  all  the  tree  of  life.  Now,  in  my 
view,  it  is  the  great  office  of  natural  selection  to  see 
to  the  growth  of  these  permanent  branches ;  and 
although  natural  selection  has  likewise  had  an  enor- 
mously large  share  in  the  origination  of  each  suc- 
cessive crop  of  leaves — nay.  let  it  be  granted  to  the 
ultra-Darwinians  for  the  sake  of  argument,  an  ex- 
clusive prerogative  in  this  respect — still,  in  my  view, 
this  is  really  the  least  important  part  of  its  work. 
Not  as  an  explanation  of  those  merely  permanent 
varieties  which  we  call  species,  but  as  an  explanation 
of  the  adaptive  machinery  of  organic  nature,  which 
has  led  to  the  construction  both  of  the  animal  and 
vegetable  kingdoms  in  all  their  divisions  do  I  regard 
the  Darwinian  theory  as  one  of  the  greatest  general- 
izations in  the  history  of  science. 


4i 
I 


It 


,1 


'  /I 


"^  lit 
«  I. 


m- 


I  have  dwelt  thus  at  some  length  upon  a  mere 
matter  of  definition  because,  as  we  shall  now  find, 
although  it  is  but  a  matter  of  definition,  it  is  fraught 
with   consequences   of  no   small   importance   to  the 


i66         Darwin^  and  after  Darwin. 


I 


1 ,. 


<(. 


'•«».< 


1,' 


}■}<  * 


general  theory  of  descent.  Starting  from  an  erroneous 
definition  of  the  theory  of  natural  selection  as  primarily 
a  theory  of  the  origin  of  species,  both  friends  and 
foes  of  the  theory  have  concluded  that  the  principle 
of  utility  must  by  hypothesis  be  of  universal  occur- 
rence so  far  as  species  are  concerned  ;  whereas,  if  once 
these  naturalists  were  to  perceive  that  their  definition 
of  the  theory  is  erroneous,  they  would  likewise 
perceive  that  their  conclusion  cannot  follow  deduc- 
tively from  the  theory  itself.  If  such  a  conclusion  is 
to  be  established  at  all,  it  can  only  be  by  other 
and  independent  evidence  of  the  inductive  kind — to 
wit,  by  actual  observation. 

Hence  we  see  the  importance  of  starting  with  an 
accurate  definition  of  the  theory  before  proceeding 
to  examine  the  doctrine  of  utility  as  of  universal 
application  to  species — a  doctrine  which,  as  just 
stated,  has  been  habitually  and  expressly  deduced 
from  the  theory.  This  doctrine  occurs  in  two  forms  ; 
or,  more  correctly,  there  are  with  reference  to  this 
subject  two  distinct  doctrines,  which  partly  coincide 
and  partly  exclude  one  another.  First,  it  is  held  by 
some  naturalists  that  all  species  must  necessarily  owe 
their  origin  to  natural  selection.  And  secondly,  it  is 
held  by  other  naturalists,  that  not  only  all  species, 
but  likewise  all  specific  characters,  must  necessarily 
do  the  same.  Let  us  consider  these  two  doctrines 
separately. 

The  first,  and  less  extensive  doctrine,  rests  on  the 
deduction  that  every  species  must  owe  its  differentiation 
as  a  species  to  the  evolution  of  at  least  one  adaptive 
character,  which  is  peculiar  to  that  species.  Although, 
when  thus  originated,  a  species  may  come  to  present 


Characters  as  Adaptive  and  Specific.    167 


an 


any  number  of  other  peculiar  characters  of  a  non- 
adaptive  kind,  these  merely  indifferent  peculiarities 
are  supposed  to  hanc^,  as  it  were,  on  the  peg  supplied 
by  the  one  adaptive  peculiarity  ;  it  is  the  latter  which 
conditions  the  species,  and  so  furnishes  an  oppor- 
tunity for  any  number  of  the  former  to  supervene. 
But  without  the  evolution  of  at  least  one  adaptive 
character  there  could  have  been  no  distinct  species, 
and  therefore  no  merely  adventitious  characters  as 
belonging  to  that  species.  I  will  call  this  the 
Huxleyan  doctrine,  because  Professor  Huxley  is  its 
most  express  and  most  authoritative  supporter. 

The  second  and  more  extensive  doctrine  I  will  call, 
for  the  same  reason,  the  Wallacean  doctrine.  This 
is,  as  already  stated,  that  it  follows  deductively  from 
the  theory  of  natural  selection,  that  not  only  all 
species,  but  even  all  the  distinctive  characters  of  every 
species,  must  necessarily  be  due  to  natural  selection  ; 
and,  therefore,  can  never  be  other  than  themselves 
useful,  or,  at  the  least,  correlated  with  some  other 
distinctive  characters  which  are  so. 

Here,  however,  I  should  like  to  remark  paren- 
thetically, that  in  choosing  Professor  Huxley  and 
Mr.  Wallace  as  severally  representative  of  the  doctrines 
in  question,  I  earnestly  desire  to  avoid  any  appearance 
of  discourtesy  towards  such  high  authorities. 

I  am  persuaded — as  I  shall  hereafter  seek  to  .show 
Darwin  was  persuaded — that  the  doctrine  of  utility  as 
universal  where  species  are  concerned,  is,  in  both  the 
above  forms,  unsound.  But  it  is  less  detrimental 
in  its  Huxleyan  than  in  its  Wallacean  form,  be- 
cause it  does  not  carry  the  erroneous  deduction  to 
so  extreme  a  point.     Therefore  let  us  first  consider 


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the  doctrine  in  its  more  restricted  form,  and  then  pro- 
ceed, at  considerably  greater  length,  to  deal  with  it  in 
its  more  extended  form. 

The  doctrine  that  all  species  must  necessarily  be  due 
to  natural  selection,  and  therefore  must  severally 
present  at  least  one  adaptive  character,  appears  to  me 
doubly  erroneous. 

In  the  first  place,  it  is  drawn  from  what  I  have 
just  shown  to  be  a  false  premiss ;  and,  in  the  second 
place,  the  conclusion  does  not  follow  even  from  this 
premiss.  That  the  premiss — or  definition  of  the  theory 
as  primarily  a  theory  of  the  origin  of  species — is  false, 
I  need  not  wait  again  to  argue.  That  the  conclusion 
does  not  follow  even  from  this  erroneous  premiss, 
a  very  few  words  will  suffice  to  prove.  For,  even  if 
it  were  true  that  natural  selection  is  primarily  a  theory 
of  the  origin  of  species,  it  would  not  follow  that  it 
must  therefore  be  a  theory  of  the  origin  of  all  species. 
This  would  only  follow  if  it  were  first  shown  that  the 
theory  is  not  merely  a  theory  of  the  origin  of  species, 
but  the  theory  of  the  origin  of  species — i.e.  that  there 
can  be  no  further  theory  upon  this  subject,  or  any 
cause  other  than  natural  selection  which  is  capable  of 
transforming  any  single  specific  type. 

Needless  to  say,  this  cannot  be  shown  by  way  of 
deduction  from  the  theory  of  natural  selection  itself — 
which,  nevertheless,  is  the  only  way  whereby  it  is 
alleged  that  the  doctrine  is  arrived  at^ 

From  the  doctrine  of  utility  as  advocated  by  Professor 

*  For  a  full  treatment  of  Piofesso-  Huxley's  views  upon  this  iubject, 
see  Appendix  II. 


Characters  as  Adaptive  and  Specific.    169 

Huxley,  we  may  now  pass  on  to  consider  it  in 
the  much  more  comprehensive  form  ndvocated  by 
Mr.  Wallace.  Of  course  it  is  obvious  that  if  the 
doctrine  is  erroneous  in  its  Huxleyan  form,  much 
more  must  it  be  so  in  its  Wallacean ;  and,  therefore, 
that  having  shown  its  erroneousness  in  its  less  extended 
application,  there  is  little  need  to  consider  it  further  in 
more  extended  form.  Lookini^,  however,  to  its 
importance  in  this  more  extended  application,  I  think 
we  ought  to  examine  it  independently  as  thus  pre- 
sented by  Mr.  Wallace  and  his  school.  Let  us  therefore 
consider,  on  its  own  merits,  the  following  statement : — 
It  follows  directly  from  the  theory  of  natural 
selection  that  not  only  all  species,  but  likewise  all 
specific  characters,  must  be  due  to  natural  selection, 
and,  therefore,  must  all  be  of  use  to  the  species 
which  present  them,  or  else  correlated  with  other 
characters  which  are  so. 

It  seems  worth  while  to  observe,  in  limine,  that 
this  doctrine  is  contradicted  by  that  of  Professor 
Huxley.  For  supposing  natural  selection  to  be  the 
only  principle  concerned  in  the  origin  of  all  species, 
it  by  no  means  follows  that  it  is  the  sole  agency 
concerned  in  the  origin  of  all  specific  characters. 
It  is  enough  for  the  former  proposition  if  only 
some  of  the  characters  distinctive  of  any  given 
species — nay,  as  he  very  properly  expresses  it,  if 
only  one  such  character — has  been  due  to  natural 
selection  ;  for  it  is  clear  that,  as  he  adds.  "  any  number 
of  indifferent  [specific]  characters "'  may  thus  have 
been  furnished  with  an  opportunity,  so  to  speak,  of 
being  produced  by  causes  other  than  natural  selection. 
Hence,  as  previously  remarked,  the  Huxleyan  doctrine, 


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170         Darwm,  and  after  Darwin. 

although  coinciding  with  the  Wallacean  up  to  the 
point  of  maintaining  utility  as  the  only  principle 
which  can  be  concerned  in  the  origin  of  species, 
designedly  excludes  the  Wallacean  doctrine  where 
this  proceeds  to  extend  any  similar  deduction  to  the 
case  of  specific  characters  ^. 

In  the  next  place,  and  with  special  reference  to  the 
Wallacean  doctrine,  it  is  of  importance  to  observe 
that,  up  to  a  certain  point  there  is  complete  agreement 
between  Darwinists  of  all  schools.  We  all  accept 
natural  selection  as  a  true  cause  of  the  origin  of  species 
(though  we  may  not  all  subscribe  to  the  Huxleyan 
deduction  that  it  is  necessarily  a  cause  of  the  origin  of 
all  species).  Moreover,  we  agree  that  specific  characters 
are  often  what  is  called  rudimentary  or  vestigial ;  and, 
once  more,  that  our  inability  to  detect  the  use  of 
any  given  structure  or  inj  tinct  is  no  proof  that  such 
a  structure  or  instinct  is  actually  useless,  seeing  that 
it  may  very  probably  possess  some  function  hitherto 
undetected,  or  possibly  undetectable.  Lastly,  we  all 
agree  that  a  structure  which  is  of  use  may  incidentally 
entail  the  existence  of  some  other  structure  which  is 
not  of  use ;  for,  in  virtue  of  the  so-called  principle  of 
correlation,  the  useless  structure  may  be  an  indirect 
consequence  of  natural  selection,  since  its  development 
may  be  due  to  that  of  the  useful  structure,  with  the 
growth  of  which  the  useless  one  is  correlated. 

Nevertheless,  while  fully  conceding  all  these  facts 
and  principles  to  the  Wallacean  party,  those  who 
think  with  Professor  Huxley — and  still  more,  of  course, 
those  few  naturalists  who  think  as  I  do— are  unable 

*  Professor  IluxhyV  views  upon  thit  matter  are  quoted  in  extenso  in 
Appendix  II. 


Characters  as  Adaptive  and  Specific.    171 

to  perceive  that  they  constitute  any  grounds  for 
holding  the  doctrine  that  all  specific  characters  are, 
or  formerly  have  been,  directly  or  indirectly  due  to 
natural  selection.  My  own  reasons  for  dissenting 
from  this  Wallaccan  doctrine  are  as  follows. 

From  what  has  just  been  said,  it  will  be  apparent 
that  the  question  in  debate  is  not  merely  a  question 
of  fact  which  can  be  settled  by  a  direct  appeal  to 
observation.  If  this  were  the  case,  systematic  natur- 
alists could  soon  settle  the  question  by  their  detailed 
knowledge  of  the  structures  which  are  severally 
distinctive  of  any  given  group  of  species.  But  so  far 
is  this  from  being  the  case,  that  systematic  naturalists 
are  really  no  better  qualiiied  to  adjudicate  upon  the 
matter  than  are  naturalists  who  have  not  devoted  so 
much  of  their  time  to  purely  diagnostic  work.  The 
question  is  one  of  general  principles,  and  as  such 
cannot  be  settled  by  appeals  to  special  cases.  For 
example,  suppose  that  the  rest  of  this  chapter 
were  devoted  to  a  mere  enumeration  of  cases  where 
it  appears  impossible  to  suggest  the  utility  of  certain 
specific  characters,  although  such  cases  could  be 
adduced  by  the  thousand,  how  shcild  I  be  met  at  the 
end  of  it  all?  Not  by  any  one  attempting  to  suggest 
the  utility,  past  or  present,  of  the  characters  named  ; 
but  by  being  told  that  they  must  all  present  some 
hidden  use,  must  be  vestigiaL  or  else  must  be  due  to 
correlation.  By  appealing  to  one  or  other  of  these  as- 
sumptions, our  opponents  are  always  able  to  escape  the 
necessity  of  justifying  their  doctrine  in  the  presence  of 
otherwise  inexplicable  facts.  No  matter  how  many 
seemingly  "  indifferent  characters  "  we  may  thus  accumu- 


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172         Darwin^  and  after  Darwin, 


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late,  Mr.  Wallace  and  his  followers  will  always  throw 
upon  us  the  impossible  burden  of  proving  the  negative, 
that  these  apparently  uselrss  characters  do  not  present 
some  hidden  or  former  use,  are  not  due  to  correlation, 
and  therefore  have  not  been  produced  by  natural  selec- 
tion. It  is  in  vain  to  retoit  that  the  burden  of  proof 
really  lies  the  other  way,  or  on  the  side  of  those  who 
affirm  that  there  is  utility  where  no  man  can  see 
it,  or  that  there  is  correlation  where  no  one  can 
detect  it.  Thus,  so  far  as  any  appeal  to  particular 
facts  is  concerned,  it  does  not  appear  that  there  is  any 
modus  vivendi.  Our  opinions  upon  the  question  are 
really  determined  by  the  views  which  we  severally 
take  on  matters  of  general  principle.  The  issue, 
though  it  has  a  biological  bearing,  is  a  logical  issue, 
not  a  biological  one:  it  turns  exclusively  on  those 
questions  of  definition  and  deduction  with  which 
we  have  just  been  dealing. 

But  although  it  thus  follows  that  we  cannot 
determine  in  fact  what  proportion  of  apparently 
useless  characters  are  or  are  not  really  useful,  we 
may  very  easily  determine  in  fact  what  proportion 
of  specific  characters  fail  to  present  any  observable 
evidences  of  utility.  Yet,  even  upon  this  question  of 
observable  fact,  it  is  surprising  to  note  the  diver- 
gent statements  which  have  of  late  years  been 
made  by  competent  writers ;  statements  in  fact  so 
diveigent  that  they  can  only  be  explained  by  some 
want  of  sufficient  thought  on  the  part  of  those 
naturalists  who  are  antecedently  persuaded  that  all 
specific  characters  must  be  either  directly  or  in- 
directly due  to  natural  selection.  Hence  they  fail 
to  give  to  apparently  useless  specific  characters  the 


Characters  as  Adaptive  and  Specific.    173 


the 


attention  which,  apart  from  any  such  antecedent 
persuasion,  they  deserve.  For  example,  a  few  years 
ago  I  incidentally  stated  in  a  paper  before  the 
Linnaean  Society,  that  "  a  large  proportional  number 
of  specific  characters  "  are  of  a  trivial  and  apparently 
unmeaning  kind,  to  which  no  function  admits  of  being 
assigned,  and  also  stated  that  Darwin  himself  had 
expressly  given  utterance  to  the  same  opinion. 
When  these  statements  were  made,  I  did  not  antici- 
pate that  they  would  be  challenged  by  anybody, 
except  perhaps,  by  Mr.  Wallace.  And,  in  order  now 
to  show  that  my  innocence  at  that  time  was  not 
due  to  ignorance  of  contemporary  thought  on  such 
matters,  a  sentence  may  here  be  quoted  from  a 
paper  which  was  read  at  the  meeting  of  the 
British  Association  of  the  same  year,  by  a  highly 
competent  systematic  naturalist,  Mr.  Henry  Seebohm, 
and  soon  afterwards  extensively  republished.  Criti- 
cizing adversely  my  then  recently  published  paper, 
he  said : — 

"  I  fully  admit  the  truth  of  this  statement ;  and  I  presume 
that  few  naturalists  would  be  prepared  to  deny  that '  distinctions 
of  specific  value  frequently  have  reference  to  structures  which 
are  without  any  utilitarian  significance  '.'  " 

But  since  that  time  the  course  of  Darwinian  specu- 
lation has  been  greatly  influenced  by  the  writings  of 
Weismann,  who,  among  other  respects  in  which  he 
out-darwins  Darwin,  maintains  the  doctrine  of  utility 
as  universal.  In  consequence  of  the  influence  which 
these  writings  have  exercised,  I  have  been  more 
recently  and  extensively  accused  of  'heresy'  to 
Darwinian  principles,  for  having  stated  that  '  a  large 
'  Geographical  Distribution  of  the  Family  Charadriidae,  p.  19. 


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174         Darwin,  and  after  Darwin. 


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proportional  number  of  specific  cliaracters  "  do  not 
admit  of  bcinj,^  proved  useful,  or  correlated  with  other 
characters  that  are  useful.  Now,  observe,  we  have 
here  a  simi)le  question  of  fact.  We  are  not  at  present 
concerned  with  the  question  how  far  the  argument 
from  ignorance  may  be  held  to  apply  in  mitigation 
of  such  cases  ;  but  we  are  concerned  only  with  the 
question  of  fact,  as  to  what  proportional  number  of 
cases  actually  occur  where  we  are  unable  to  suggest 
the  use  of  specific  characters,  or  the  useful  characters 
with  which  these  apparently  useless  ones  are  corre- 
lated. I  maintain,  as  a  matter  of  fact,  that  the  cases 
in  question  embrace  "  a  large  proportional  number 
of  specific  characters."  On  the  other  hand,  I  am 
accused  of  betraying  ignorance  of  s[)ecies,  and  of  the 
work  of  "species-makers,"  in  advancing  this  state- 
ment; and  have  been  told  by  Mr.  Wallace,  and 
others  of  his  school,  that  there  is  absolutely  no 
evidence  to  be  derived  from  nature  in  support  of  my 
views.  Well,  in  the  first  place,  if  this  be  the  case, 
it  is  somewhat  remarkable  that  a  large  body  of 
competent  naturalists,  such  as  Bronn,  Broca,  Nageli, 
Kerner,  Sachs,  De  Vries,  Focke,  Henslow,  Haeckel, 
Kolliker,  Eimer,  Giard.  Pascoe,  Mivart,  Seebohm, 
Lloyd  Morgan,  Dixon.  Beddard,  Gcddes  Gulick,  and 
also,  as  we  shall  presently  see  Darwin  himself,  should 
have  fallen  into  the  same  error.  And  it  is  further 
remarkable  that  the  more  a  man  devotes  himself  to 
systematic  work  in  any  particular  department — 
whether  as  an  ornithologist,  a  conchologist,  an  ento- 
mologist, and  so  forth — the  less  is  he  disposed  to 
accept  the  dogma  of  specific  characters  as  universally 
adaptive  characters.     But,  in  the  second  place,  and 


V- 


Characters  as  Adaptive  and  Specific.    175 


quittinc^  considerations  of  mere  authority,  I  appeal 
to  the  facts  of  nature  themselves ;  and  will  nov. 
proceed,  as  briefly  as  possible,  to  indicate  the  result 
of  such  an  appeal. 

For  the  following  reasons,  that  birds  and  mam- 
mals seem  to  furnish  the  best  field  for  testing  the 
question  by  direct  observation.  First,  these  classes 
present  many  genera  which  have  been  more  care- 
fully worked  out  than  is  usually  the  case  with 
genera  of  invertebrates,  or  even  of  cold-blooded 
vertebrates.  Secondly,  they  comprise  many  genera 
each  including  a  large  number  of  species,  whose 
habits  and  conditions  of  life  are  better  known  than 
is  the  C£*se  with  species  belonging  to  large  genera 
of  other  classes.  Thirdly,  as  birds  and  mammals 
represent  the  highest  products  of  evolution  in  respect 
of  organization,  a  more  severe  test  is  imposed  than 
could  be  imposed  elsewhere,  when  the  question  is 
as  to  the  utility  of  specific  characters;  for  if  these 
highest  products  of  organization  fail  to  reveal,  in  a 
large  proportional  number  of  cases,  the  utility  of  their 
specific  characters,  much  more  is  this  likely  to  be  the 
case  among  organic  beings  which  stand  lower  in  the 
scale  of  organization,  and  therefore,  ex  hypothesis 
are  less  elaborate  products  of  natural  selection. 
Fourthly,  and  lastly,  birds  and  mammals  are  the 
classes  which  Mr.  Wallace  has  expressly  chosen  to 
constitute  his  ground  of  argument  with  regard  to 
the  issue  on  which  we  are  now  engai^ed. 

It  would  take  far  too  long  to  show,  even  in  epi- 
tome, the  results  of  this  inquiry.  Therefore  I  will 
only  state  the  general  upshot.  Choosing  genera  of 
birds  and   mammals  which  contain  a  large  number 


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of  species  whose  diagnostic  characters  have  been 
worked  out  with  most  completeness,  I  restricted 
the  inquiry  to  specific  distinctions  of  colour,  not 
only  for  the  sake  of  having  a  uniform  basis  for 
comparisons,  but  still  more  because  it  seemed  that 
the  argument  from  our  ignorance  of  possibly  un- 
known uses  could  be  more  successfully  met  in  the 
case  of  slight  differences  of  colour  or  of  shading, 
than  in  that  of  any  differences  of  structure  or  of 
form.  Finally,  after  tabulating  all  the  differences  of 
colour  which  are  given  as  diagnostic  of  each  species 
in  a  genus,  and  placing  in  one  column  those  which 
may  conceivably  be  useful,  while  placing  in  another 
column  those  of  which  it  appeared  inconceivable 
tha.t  any  use  could  be  suggested,  I  added  up  the 
figures  in  the  two  columns,  and  thus  obtained  a 
grand  total  of  all  the  specific  characters  of  the 
genus  in  respect  of  colours,  separated  into  the  two 
classes  of  conceivably  useful  and  apparently  useless. 
Now,  in  all  cases  the  apparently  useless  characters 
largely  preponderated  over  the  conceivably  useful 
ones ;  and  therefore  I  abundantly  satisfied  myself 
regarding  the  accuracy  of  my  previous  statement, 
that  a  large  proportional  number— if  not  an  actual 
majority — of  specific  characters  belong  to  the  latter 
category. 

The  following  is  a  brief  abstract  of  these  results. 

With  respect  to  Birds,  a  large  number  of  cases 
were  collected  wherein  the  characters  of  allied 
species  differ  from  one  another  in  such  minute 
respects  of  colour  or  shading,  that  it  seemed  unrea- 
sonable to  suppose  them  due  to  any  selective 
value  to  the   birds   in    question.     It  is   needless — 


Characters  as  Adaptive  and  Specific.    177 


even  if  it  were  practicable  on  the  present  occa- 
sion— to  adduce  this  evidence  in  detail,  since  an 
exceedingly  good  sample  of  it  may  be  found  in 
a  small  book  which  is  specially  devoted  to  consider- 
ing the  question  in  its  relation  to  birds.  I  allude 
to  an  essay  by  Mr.  Charles  Dixon,  entitled  Evolu- 
tion without  Natural  Selection  (1H85).  In  this  work 
Mr.  Dixon  embodies  the  results  of  five  years'  •  care- 
ful working  at  the  geographical  distribution  and 
variations  of  plumage  of  Palaearctic  birds  and  their 
allies  in  various  other  parts  of  the  world" ;  ind 
shows,  by  a  large  accumulation  of  facts,  not  only 
that  there  is  no  utility  to  be  suggested  in  reference 
to  the  minute  or  trivial  differences  of  colouration 
which  he  describes ;  but  also  that  these  differen^^.^ 
are  usually  correlated  with  isolation  on  the  one 
hand,  or  with  slight  differences  of  climate  on  the 
other.  Now  it  will  be  shown  later  on  that  both 
these  agents  can  be  proved,  by  independent  evidence, 
capable  of  inducing  changes  of  specific  type  with- 
out reference  to  utility :  therefore  the  correlation 
which  Mr.  Dixon  unquestionably  establishes  between 
apparently  useless  (because  utterly  trivial)  specific 
distinctions  on  the  one  hand,  and  isolation  or 
climatic  change  on  the  other,  constitutes  additional 
evidence  to  show  that  the  uselessness  is  not  only 
apparent,  but  real.  Moreover  I  have  collected  a 
number  of  cases  where  such  minute  differences  of 
colour  between  allied  species  of  birds  happen  to 
affect  parts  of  the  plumage  which  are  concealed — as 
for  instance,  the  breast  and  abdomen  of  creepers.  In 
such  cases  it  seems  impossible  to  suggest  how  natural 
selection  can  have  operated,  seeing   that   the  parts 


1 
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178         Darwin^  and  after  Darwin, 


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affected  are  not  exposed  to  the  view  either  of  enemies 
or  of  prey. 

Analogous  illustrations  to  any  amount  may  be  drawn 
from  Mammals.  For  instance,  I  have  worked  through 
the  Marsupials  with  the  aid  of  Mr.  Oldfield  Thomas' 
diagnostic  description  of  their  numerous  species. 
Now,  let  us  take  any  one  of  the  genera,  such  as 
the  kangaroos.  This  comprises  23  species  living  on 
an  island  continent  of  high  antiquity,  and  not  ex- 
posed to  the  depredations  of  any  existing  carnivor- 
ous enemies ;  so  that  there  is  here  no  present  need 
to  vary  colour  for  purposes  of  protection.  More- 
over, in  all  cases  the  diagnostic  distinctions  of 
colour  are  so  exceedingly  trivial,  that  even  if  large 
carnivora  were  recently  abundant  in  Australia,  no  one 
could  reasonably  suggest  that  the  differences  in 
question  would  then  have  been  protective.  On  an 
average,  each  of  the  23  species  presents  rather  more 
than  20  peculiarities  of  shading,  which  are  quoted 
as  specifically  diagnostic.  Altogether  there  are  474 
of  these  peculiarities  distributed  pretty  evenly  among 
the  23  species  ;  and  in  no  case  can  I  conceive  that 
utility  can  be  suggested. 


Hitherto  we  have  been  considering  the  question  of 
fact,  as  to  whether  "a  lar^e  proportional  number 
of  specific  characters  "  do  or  do  not  admit  of  having 
their  utility  demonstrated,  or  even  so  much  as  plaus- 
ibly suggested.  In  the  result,  I  can  only  conclude 
that  this  question  of  fact  is  really  not  an  open  one, 
seeing  that  it  admits  of  an  abundantly  conclusive 
answer  by  any  naturalist  who  will  take  the  trouble 
to   work   through   the    species   of   any  considerable 


'if 


Characters  as  Adaptive  and  Specific.    179 

number  of  genera  in  the  way  above  indicated.  Rut 
althougli  the  question  of  fact  is  thus  really  closed, 
there  remains  a  more  ultimate  question  as  to  its 
theoretical  interpretation.  P'or,  as  already  pointed 
out.  no  matter  how  great  an  accumulation  of  such 
facts  may  be  collected,  our  opponents  are  always  able 
to  brush  them  aside  by  their  a  priori  appeal  to  the 
argument  from  ignorance.  In  elTect  they  say — We 
do  not  care  for  any  number  of  thousands  of  such 
facts  ;  it  makes  no  difference  to  us  what  '•  proportional 
number"  of  specific  characters  fail  to  show  evidence 
of  utility  ;  yoi'  are  merely  beating  the  air  by  adducing 
them,  for  we  are  already  persuaded,  on  antecedent 
grounds,  that  all  specific  characters  must  be  either 
themselves  useful,  or  correlated  with  others  that  are, 
whether  or  not  we  can  perceive  the  utility,  or  suggest 
the  correlation. 

To  this  question  of  theoretical  interpretation,  there- 
fore, we  mu.st  next  address  ourselves.  And  here, 
first  of  all,  I  should  like  to  point  out  how  sturdy  must 
be  the  antecedent  conviction  of  our  opponents,  if 
they  are  to  maintain  it  in  the  face  of  such  facts  as 
have  just  been  adduced.  It  must  be  remembered 
that  this  antecedent  conviction  is  of  a  most  uncom- 
promising kind.  By  its  own  premisses  it  is  committed 
to  the  doctrine  that  all  specific  characters,  without 
a  single  exception,  must  be  either  useful,  vestigial,  or 
correlated.  Well,  if  such  be  the  case,  is  it  not  some- 
what astonishing  that  out  of  474  differences  of  colour 
which  are  distinctive  of  the  23  species  of  the  genus 
Macropus,  no  single  one  appears  capable  of  having  any 
utility  demonstrated,  or  indeed  so  much  as  suggested  ? 
For  even  the  recent  theory  that  slight  differences  of 

N    2 


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i8o         Darwin,  and  after  Darwin, 

colour,  which  cannot  be  conceived  as  serving  any 
other  purpose,  may  enable  the  sexes  of  the  same 
species  quickly  to  recognize  each  other,  is  not  here 
available.  The  species  of  the  genus  Macropus  are 
more  conspicuously  distinguished  by  differences  of  size 
and  form  than  by  these  minute  differences  of  colour ; 
and  therefore  no  such  use  can  be  attributed  to  the 
latter.  And,  as  previously  stated,  even  within  the 
order  Marsupialia  the  genus  Macropus  is  not  at  all 
exceptional  in  this  respect  ;  so  that  by  including 
other  genera  of  the  order  it  would  be  easy  to  gather 
such  apparently  indifferent  specific  characters  by 
the  hundred,  without  any  one  of  them  presenting 
evidence — or  even  suggestion — of  utility.  How  robust 
therefore  is  the  faith  of  an  a  priori  conviction  which 
can  stand  against  such  facts  as  these!  What,  then, 
are  the  a  priori  grounds  on  which  it  stands? 
Mr.  Wallace,  the  great  leader  of  this  school  of  thought, 
says : — 

"  It  is  a  necessary  deduction  from  the  theory  of  natural  selec- 
tion, that  none  of  the  definite  facts  of  organic  nature,  no  special 
organ,  no  characteristic  form  or  marking,  no  peculiarities  of 
instinct  or  of  habit,  no  relations  between  species  or  between 
groups  of  species,  can  exist,  but  which  must  now  be,  or  once 
have  been,  useful  to  the  individuals  or  the  races  which  possess 
them  \** 

Here,  then,  we  have  in  brief  compass  the  whole 
essence  of  our  opponents'  argument.  It  is  confessedly 
an  argument  a  priori,  a  deduction  from  the  theory 
of  natural  selection,  a  supposed  consequence  of  that 
theory  which  is  alleged  to  be  so  necessary  that  to 

'  Contributions  to  the  Theory  of  Natural  Selection,  p.  47  (1870)  ;  re- 
published in  189a. 


Characters  as  Adaptive  and  Specific.    i8i 


dispute  the  conscciucnce  is  tantamount  to  denying  the 
theory  from  which  it  is  derived.  In  short,  as  before 
stated,  it  is  a  question  of  theory,  not  a  question  of 
fact :  our  difference  of  opinion  is  logical,  not  biological : 
it  depends  on  our  interpretation  of  principles,  not 
on  our  observation  of  species.  It  will  therefore  be 
my  endeavour  to  show  that  the  reasoning  in  question 
is  fallacious  :  that  it  is  not  a  necessary  deduction 
from  the  theory  of  natural  selection  that  no  character- 
istic form  or  marking,  no  peculiarities  of  instinct  or 
of  habit,  can  exist,  but  which  must  now  be,  or  once 
have  been,  useful,  or  correlated  with  some  other 
peculiarity  that  is  useful. 

'*  The  tuft  of  hair  on  the  breast  of  a  wild  turkey- 
cock  cannot  be  of  any  use,  and  it  is  doubtful  whether 
it  can  be  ornamental  in  the  eyes  of  the  female  bird  ; 
— indeed,  had  the  tuft  appeared  under  domestication, 
it  would  have  been  called  a  monstrosity  ^.'* 

As  a  matter  of  common  sense,  unprejudiced  by 
dogma,  this  appears  to  be  a  perfectly  sound  judgement; 
but  if  Wallace  had  asked  Darwin  to  prove  such 
a  negative,  Darwin  could  only  have  replied  that  it 
was  for  Wallace  to  prove  the  affirmative-  and  thus 
the  issue  would  have  been  thrown  back  upon  a  dis- 
cussion of  genr  "al  principles.  Then  Wallace  would 
have  said — "  The  assertion  of  inutility  in  the  case  of 
,'iny  organ  or  peculiarity  which  is  not  a  rudiment  or 
a  correlation  is  not,  and  can  never  be,  the  statement 
of  a  fact,  but  merely  an  expression  of  our  ignorance  of 
its  purpose  or  origin  '^T  Darwin,  however,  would  have 
replied : — "  Our  ignorance  of  the  laws  of  variation  is 

'  Orifcin  of  Species,  p.  70  :  italics  mine. 
'  Darwinism,  p.  137  :  italics  mine. 


W 

in 


i 

14 


m 


i82         Darzvin,  and  after  Darwin. 


M 


»Ll. 


I 'In'"*,* 

Si*.'  !►;* 


s  •> 


profound  "  :  and  while,  on  this  account,  we  ought  "  to 
be  extremely  cautious  in  pretending  to  decide  what 
structures  are  now,  or  have  formerly  been,  of  use  to 
each  species"  in  point  of  fact,  *' there  can  be  little 
doubt  that  the  tendency  to  vary  in  the  same  manner 
has  often  been  so  strong,  that  all  individuals  of  the 
same  species  have  been  similarly  modified  without  the 
aid  of  any  form  of  selection  ^." 

It  will  be  my  endeavour  in  the  following  discussion 
to  show  that  Darwin  would  have  had  an  immeasurable 
advantage  in  this  imaginary  debate. 

To  begin  with,  Wallace's  deductive  argument  is 
a  clear  case  of  circular  reasoning.  We  set  out  by  infer- 
ring that  natural  selection  is  a  cause  from  numberless 
cases  of  observed  utility  as  an  effect :  yet,  when  "  in 
a  large  proportional  number "  of  cases  we  fail  to 
perceive  any  imaginable  utility,  it  is  argued  that 
nevertheless  utility  must  be  there,  since  otherwise 
natural  selection  could  not  have  been  the  cause. 

Be  it  observed,  in  any  given  case  we  may  propeiiy 
anticipate  utility  as  probable,  even  where  it  is  not 
perceived ;  because  there  are  already  so  enormous 
a  number  of  cases  where  it  is  perceived,  that,  if  the 
principle  of  natural  selection  be  accepted  at  all,  we  must 
conclude  with  Darwin  that  it  is  '"  the  main  means  of 
modification."  Therefore,  in  particular  cases  of  un- 
perceived  utility  we  may  take  this  antecedent  prob- 
ability as  a  guide  in  our  biological  researches — as  has 


III 


*  Origin  of  Species,  ji.  72  :  Mr.  Wallace  himself  quotes  this  passage 
{Darwinism,  p.  141);  but  says  with  regard  to  it  "the  importanl  word 
*  all '  is  probably  an  oversight."  In  the  Appendix  i^ll),  on  Darwin's 
views  touching  the  doctrine  of  utility  I  adduce  a  number  of  precisely 
equivalent  passages,  derived  from  all  his  different  works  on  evolution, 
and  every  one  of  them  presenting  "  the  important  word  '  all.' " 


\-- 


\  '■ 


Characters  as  Adaptive  and  Specific,    183 


been  done  with  such  brilliant  success  both  by  Darwin 
and  Wallace,  as  well  as  by  many  of  their  followers. 
But  this  is  a  very  different  thing  from  laying  down 
the  universal  maxim,  that  in  all  cases  utility  must 
be  present,  whether  or  not  we  shall  ever  be  able  to 
detect  it  ^.  For  this  universal  maxim  amounts  to  an 
assumption  that  natural  selection  has  been  the  '^  exclu- 
sive means  of  modification."  That  it  has  been  '•  the 
main  means  of  modification  "  is  proved  by  the  gener- 
ality of  the  observed  facts  of  adaptation.  That  it  has 
been  *'  the  exclusive  means  of  modification,"  with  the 
result  that  these  facts  are  universal,  cannot  be  thus 
proved  by  observation.  Why,  then,  is  if:  alleged  ? 
Confessedly  it  is  alleged  by  way  of  deduction  from 
the  theory  of  natural  selection  iiself.  Or,  as  above 
stated,  after  having  deduced  the  theory  from  the  facts, 
it  is  sought  to  deduce  the  facts  from  the  theory. 

Thus  far  I  have  been  endeavouring  to  show 
that  the  universality  of  adaptation  cannot  be  inferred 
from  its  generality,  or  from  the  theory  of  natural  selec- 
tion itself.  But,  of  course,  the  case  would  be  quite 
different  if  there  were  any  independent  evidence — or 
rather,  let  us  say,  any  logical  argument — to  show  that 
natural  selection  is  '*  the  exclusive  means  of  modifi- 
cation.*' For  in  this  event  it  would  no  longer  involve 
circular  reasoning  to  maintain  that  all  s'lecific  char- 
acters  are  likewise  adaptive  characters.  It  might 
indeed  appear  antecedently  improbable  that  no 
other  principle  than  natural  selection  can  possibly 
have  been  concerned  in  the  differentiation  of  those 
relatively  permanent  varieties  which  we  call  species — 
that  in  all  the  realm  of  organic  nature,  and  in  all  the 

'  See  Introductory  Chapter,  p.  ao. 


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184         Darwin,  and  after  DarLvin, 

complexities  of  living  processes,  tliere  is  no  room  for 
any  other  influence  in  the  production  of  change,  even 
of  the  most  trivial  and  apparently  unmeaning  kind. 
But  if  there  were  any  good  evidence  or  logical  argu- 
ment to  the  contrary,  this  antecedent  presumption 
would  have  to  give  way  ;  and  the  certainty  that  all 
specific  characters  are  likewise  adaptive  characters 
would  be  determined  by  the  cogency  of  such  evidence 
or  argument  as  could  be  adduced.  In  short,  we  are 
not  entitled  to  conclude — and  still  less  does  it  follow 
"  as  a  necessary  deduction  from  the  theory  of  natural 
selection  " — that  all  the  details  of  specific  differentia- 
tion must  in  every  case  be  either  useful,  vestigial,  or 
correlated,  unless  it  has  been  previously  shown,  by 
independent  evidence,  or  accurate  reasoning,  that  there 
is  no  room  for  any  other  priitciple  of  specific  change. 

This,  apparently,  is  the  centval  core  of  the  question. 
Therefore  I  will  now  proceed  to  consider  such  argu- 
ments as  have  been  adduced  to  prove  that,  other 
than  natural  selection,  there  cati  have  been  no  "  means 
of  modification.*'  And,  after  having  exhibited  the 
worthlessness  of  these  arguments,  I  will  devote  the 
next  chapter  to  showing  that,  as  a  matter  of  ob- 
servable fact,  there  are  a  considerable  number  of 
other  principles,  which  can  be  proved  to  be  capable 
of  producing  such  minute  ciifferencts  of  form  and 
colour  as  "in  a  large  proportional  number"  of  cases 
constitute  diagnostic  distinctions  between  species  and 
species. 

First,  then,  for  the  reasons  a  priori — and  they 
are  confessedly  a  priori — which  have  been  adduced 
to  prove  that  natural  selection  has  been  what  in 
Darv'in's   opinion   it   has  not  been, — "  the  exclusive 


Characters  as  Adaptive  and  Specific.    185 

means  of  modification."  Dtsreijjarding  the  Lamarckian 
factors — which,  even  if  valid,  have  but  little  relation  to 
the  present  question,  seeing  that  they  are  concerned, 
almost  exclusively,  with  the  evolution  of  adaptive 
characters — it  is  alleged  that  natural  selection  must 
occupy  the  whole  field,  because  no  other  principle 
of  change  can  be  allowed  to  operate  in  the  presence 
of  natural  selection  Now,  I  fully  agree  that  this 
statement  may  hold  as  regards  any  principle  of  change 
which  is  deleterious ;  but  clearly  it  does  not  hold 
as  regards  any  principle  which  is  merely  neutral. 
If  any  one  were  to  allege  that  specific  characters 
are  frequently  detrimental  to  the  species  presenting 
them,  he  would  no  doubt  lay  himself  open  to  the 
retort  that  natural  selection  could  not  allow  such 
characters  to  persist ;  or,  which  amounts  to  the  same 
thing,  that  it  does  "  necessarily  follow  from  the  theory 
of  natural  selection "  that  specific  characters  can 
never  be  in  any  large  number,  or  in  any  large 
measure,  harmftd  to  the  species  presenting  them. 
But  where  the  statement  is  that  specific  characters 
are  frequently  indifferent — again  to  use  Professor 
Huxley's  term — the  retort  loses  all  its  relevancy.  No 
reason  has  ever  been  shown  why  natural  selection  should 
interfere  with  merely  indifferent  characters,  supposing 
such  to  have  been  produced  by  any  of  the  agencies 
which  we  shall  presently  have  to  consider.  Therefore 
this  argument — or  rather  assertion — goes  for  nothing. 
The  only  other  argument  I  have  met  with  on  this 
side  of  the  question  is  one  that  has  recently  been 
adduced  by  Mr.  Wallace.     He  says  : — 

"  One   very    weighty  objection    to    the    theory  that   specific 
characters   can  ever  be  wholly  useless   appears  to  have  been 


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i86         Darwifij  and  after  Darwin, 

overlooked  by  those  who  have  maintained  the  frequency  of 
such  characters,  and  that  is,  their  almost  necessary  instability  *." 

This  argument  he  proceeds  to  elaborate  at  con- 
siderable length,  but  fails  to  perceive  what  appears 
to  me  the  obvious  answer.  Provided  that  the  cause 
of  the  useless  character  is  constant,  there  is  no 
difficulty  in  understanding  why  the  character  is 
stable.  Utility  is  not  the  onl)^  principle  that  can 
lead  to  stability :  any  other  principle  must  do  the 
same,  provided  that  it  acts  for  a  sufficient  length 
of  time,  and  with  a  sufficient  degree  of  uniformity, 
on  all  the  mdividuals  of  a  species.  This  is  a  con- 
sideration the  cogency  of  which  was  clearly  recog- 
nized by  Darwin,  as  the  following  quotations  will 
show.  Speaking  of  unadaptive  characters,  he  says 
they  may  arise  as  merely 

"  fluctuating  variations,  which  sooner  or  later  become  constant 
through  the  nature  of  the  organism  and  of  surrounding  conditions, 
but  not  through  natural  selection  V* 

Elsewhere  we  read  : — 

"  Each  of  the  endless  variations  which  we  see  in  the  plumage 
of  our  fowls  must  have  had  some  efficient  cause ;  and  if  the 
sa?ne  cause  were  to  act  utdfornily  during  a  long  series  of  genera- 
tions on  mafiy  individuals,  all  probably  would  be  modified  in 
the  same  manner." 

As  special  illustrations  of  this  fact  I  may  quote 
the  following  cases  froni  Darwin's  works. 

"Dr.  Bachman  states  that  he  has  seen  turkeys  raised  from 
the  eggs  of  wild  species,  lose  their  metallic  tints,  and  become 
spotted  in  the  third  generation.  Mr.  Yarrell  many  years  ago 
informed  me  that  the  wild  ducks  bred  in  St.  James'  Park  lost 

'  Darwinism,  p.  138. 

'  Origin  of  Species,  p.  176:  italics  mine,  as  also  in  the  following. 


I 


Characters  as  Adaptive  and  Specific.    187 


I 


their  true  plumage  after  a  few  generations.  An  excellent 
observer  (Mr.  Hewitt)  .  .  .  found  that  he  could  not  breed  wild 
ducks  true  for  more  than  five  or  six  generations,  as  they  proved 
so  much  less  beautiful.  The  white  collar  round  the  neck  of  the 
mallard  became  broader  and  more  irregular,  and  white  feathers 
appeared  in  the  duckling's  wings  &c.^  " 

Now,  such  cases — to  which  numberless  others  might 
be  added — prove  that  even  the  subtle  and  incon- 
spicuous causes  incidental  to  domestication  are 
capable  of  inducing  changes  of  specific  character 
quite  as  great,  and  quite  as  ''stable,"  as  any  that 
in  a  state  of  nature  are  taken  to  constitute  specific 
distinctions.  Yet  there  can  here  be  no  suggestion 
of  utility,  inasmuch  as  the  change  takes  place  in  the 
course  of  a  few  generations,  and  therefore  without 
leaving  time  for  natural  selection  to  come  into  play — 
even  if  it  ever  could  come  into  play  among  the 
sundry  domesticated  birds  in  question. 

But  the  facts  of  domestication  also  make  for  the 
same  conclusion  in  another  way — namely,  by  proving 
that  when  time  enough  has  been  allowed  for  the  pro- 
duction of  useless  changes  of  greater  magnitude, 
such  changes  are  not  infrequently  produced.  And 
the  value  of  this  line  of  evidence  is  that,  great  as  are 
the  changes,  it  is  impossible  that  either  natural  or 
artificial  selection  can  have  been  concerned  in  their 
production.  It  will  be  sufficient  to  give  two  examples 
— both  with  regard  to  structure. 

The  first  I  will  render  in  the  words  whereby  it 
has  already  been  stated  in  my  own  paper  01. 
Physiological  Selection,  because  I  should  like  to  take 
this  opportunity  of  answering  Mr.  Wallace's  objection 

to  it. 

*  Var.  vol.  ii.  p.  250. 


11 


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i88         Darwin^  and  after  Darwin, 

"Elsewhere  {Origin  of  Species,  p.  158)  Mr.  Darwin  points  out 
that  modifications  which  appear  to  present  obvious  utility  are 
often  found  on  further  examination  to  be  really  useless.  This 
latter  consideration,  therefore,  may  be  said  to  act  as  a  foil  to 
the  one  against  which  I  am  arguing,  namely,  that  modifications 
which  appear  to  be  useless  may  nevertheless  be  useful.  But 
here  is  a  still  more  suggestive  consideration,  also  derived  from 
Mr.  Darwin's  writings.  Among  our  domesticated  productions 
changes  of  structure— or  even  structures  wholly  new— not  unfre- 
quently  arise,  which  are  in  every  way  analogous  to  the  apparently 
useless  distinctions  between  wild  species.  Take,  for  example, 
the  following  most  instructive  case : — 


Fig.  2.— Old  Irish  Pig,  showing  jaw-appendages  (after  Richardson). 


^1 


^b 


M 


"  *  Another  curious  anomaly  is  offered  by  the  appendages 
described  by  M.  Eudes-Deslongchamps  as  often  characterizing 
the  Normandy  pigs.  These  appendages  are  alwayf,  attached 
to  the  same  spot,  to  the  corners  of  the  jaws  ;  they  are  cylindrical, 
about  three  inches  in  length,  covered  with  bristles,  and  with 
a  pencil  of  bristles  rising  out  of  a  sinus  on  one  side  ;  they  have 
a  cartilaginous  centre  with  two  small  longitudinal  muscles; 
they  occur  either  symmetrically  on  both  sides  of  the  face, 
or  on  one  side  alone.  Richardson  figures  them  on  the  gaunt 
old    Irish   Greyhound  pig;    and  Nathusius  states  that  they 


Characters  as  Adaptive  and  Specific.    189 

occasionally  appear  in  all  the  long-eared  races,  but  are  not 
strictly  inherited,  for  they  occur  or  fail  in  the  animals  of  the 
same  litter.  As  no  wild  pigs  are  known  to  have  analogous 
appendages,  we  have  at  present  no  reason  to  suppose  that  their 
appearance  is  due  to  reversion ;  and  if  this  be  so,  we  are  forced 
to  admit  that  a  somewhat  complex,  though  apparently  useless, 
structure  may  be  suddenly  developed  without  the  aid  of 
selection  *.' " 

To  this  case  Mr.  Wallace  objects : — 

"  But  it  is  expressly  stated  that  they  are  not  constant :  they 
appear  'frequently'  or  'occasionally,'  they  are  *not  strictly 
inherited,  for  they  occur  or  fail  in  animals  of  the  same  litter ' ; 
and  they  are  not  always  syminetrical,  sometimes  appearing  on 
one  side  of  the  face  alone.  Now,  whatever  may  be  the  cause 
or  explanation  of  these  anomalous  appendages,  they  cannot  be 
classed  with  'specific  characters,'  the  most  essential  features 
of  which  are,  that  they  are  symmetrical,  that  they  are  inherited, 
and  that  they  are  constant  V 

But,  to  begin  with,  I  have  not  classed  these  ap- 
pendages with  "  specific  characters,"  nor  maintained 
that  Normandy  pigs  ought  to  be  regarded  as  specifi- 
cally distinct  on  account  of  them.  What  I  said 
was: — 

"  Now,  if  any  such  structure  as  this  occurred  in  a  wild  species, 
and  if  any  one  were  to  ask  what  is  the  use  of  it,  those  who  rely 
on  the  argument  from  ignorance  would  have  a  much  stronger 
case  tlian  they  usually  have ;  for  they  might  point  to  the 
cartilage  supplied  with  muscles,  and  supporting  a  curious 
arrangement  of  bristles,  as  much  too  specialized  a  structure  to 
be  wholly  meaningless.  Yet  we  happen  to  know  that  this 
particular  structure  is  wholly  meaningless  V 


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*   Variation,  &c.  vol.  i.  pp.  78-79.  '  Darwinism,  pp.  139-40. 

'  Mr.    Wallace    deems   the    concluding  words   "rather   confident.** 
I  was  not,  however,  before  aware  that  he  extended  his  a  priori  views  on 


hi ;  : 


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19c        Darwm,  and  after  Darwin. 

In  the  next  place,  is  it  either  fair  or  reasonable  to 
expect  that  a  varietal  character  of  presumably  very 
recent  origin  should  be  as  strongly  inherited — and 
theVefore  as  constant  both  in  occurrence  and  sym- 
metry— as  a  true  specific  character,  say,  of  a  thousand 
times  its  age?  Even  characters  of  so-called  "  constant 
varieties  "  in  a  state  of  nature  are  usually  less  constant 
than  specific  characters ;  while,  again,  as  Darwin 
says,  "  it  is  notorious  that  specific  characters  are 
more  variable  than  generic,"  -the  reason  in  both 
cases  being,  as  he  proceeds  to  show,  that  the  less 
constant  characters  are  characters  of  more  recent 
origin,  and  therefore  less  firmly  fixed  by  heredity'. 
Hence  I  do  not  understand  how  Mr.  Wallace  can 
conclude,  as  he  does,  "  that,  admitting  that  this  peculiar 
appendage  is  wholly  useless  and  meaningless,  the  fact 
would  be  rather  an  argument  against  specific  charac- 
ters being  also  meaningless,  because  the  latter  never 
have  the  characteristics  [i.e.  inconstancy  of  occur- 
rence, form,  and  transmission]  which  this  particular 
variation  possesses^."  Mr.  Wallace  can  scarcely 
suppose  that  when  specific  characters  first  arise, 
they  present  the  three-fold  kind  of  constancy 
to  which  he  here  alludes.  But,  if  not,  can  it  be 
denied  that  these  peculiar  appendages  appear  to 
be  passing  through  a  phase  of  development  which 
all '*  specific  characters  "  must  have  passed  through, 


V. 


utility  to  domesticated  varieties  which  are  bred  for  the  slaughter- 
house. If  he  now  means  to  indicate  that  these  appendages  are  possibly 
due  to  natural  selection,  he  is  surely  going  very  far  to  save  his 
a  priori  dogma  ;  and  in  the  case  next  adduced  will  have  to  go  further 
still. 

'  Origin  of  Species,  pp.  123-3. 

"■'  Danvinism,  p.  140. 


Characters  as  Adaptive  and  Specific.    191 


before    they   have    had    time    enough   to   be   firmly 
fixed  by  heredity  ^  ? 

If,  however,  even  this  should  be  denied,  what 
will  be  said  of  the  second  case,  that  of  the  niata 
cattle  ? 

"Isawtw  herds  on  the  northern  bank  of  the  Plata.  .  .  .  The 
forehead  is  very  short  and  broad,  with  the  nasal  end  of  the  skull, 
together  with  the  whole  plane  of  the  upi)or  molar-teeth,  curved 
upwards.  The  lower  jaw  projects  beyond  the  upper,  and  has 
a  corresponding  upward  curvature.  .  .  .  The  skull  which  I  pre- 
sented to  the  College  of  Sun^eons  has  been  thus  described 
by  Professor  Owen.  '  It  is  remarkable  from  the  stunted  develop- 
ment of  the  nasals,  premaxillaries,  and  fore  part  of  the  lower 
jaw,  which  is  unusually  curved  upwards  to  come  into  contact 
with  the  premaxillaries.  The  nasal  bones  arc  about  one-third 
the  ordinary  length,  but  retain  almost  thc'r  normal  brea'llh. 
The  triangular  vacuity  is  left  between  them  anrl  the  frontal 
and  lachrymal,  which  latter  bone  articulates  with  the  prc- 
maxillary,  and  thus  excludes  the  maxillary  from  any  junction 

'  In  the  next  paragraph  Mr.  Wallace  says  that  the  appendages  in 
question  "  are  apparently  of  the  same  nature  as  the  *  sjiorts '  that  arise 
in  oar  domesticated  productions,  but  which,  as  Mr.  Oarwiti  says, 
without  the  aid  of  selection  would  soon  disappear."  But  I  cannot 
find  that  Mr.  Darwin  has  made  any  sucli  statement :  what  he  does 
say  is,  that  whether  or  not  a  useless  peculiarity  will  soon  disappear 
without  the  aid  of  selection  depends  upon  the  natiirc  of  the  causes  which 
produce  it.  If  these  causes  are  of  a  merely  transitory  nature,  the 
peculiarity  will  also  be  transitory ;  but  if  the  causes  be  constant,  so  will 
be  the  result.  Again,  the  point  to  be  noticed  about  this;  "  sport "  is, 
that,  unlike  what  is  usually  understood  by  a  "sport,"  it  affects  a  whole 
race  or  breed,  is  transmitted  by  sexual  propagation,  and  has  already 
attained  so  definite  a  si/e  and  structure,  that  it  can  only  be  reasonably 
accounted  for  by  supposing  the  continued  operation  of  some  constant 
cause.  This  cause  can  scarcely  be  correlation  of  growth,  since  closely 
similar  appendages  are  often  seen  in  so  different  an  animal  as  a 
goat.  Here,  also,  they  run  in  breeds  or  strains,  are  strongly  inherited, 
and  more  "constant,"  as  well  as  more  "  symmetrical "  than  they  are 
in  pigs.  This,  at  all  events,  is  the  account  I  have  received  of  them 
from  goat-breeders  in  Switzerland. 


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Characters  as  Adaptive  and  Specific.    193 


with  the  nasal.'  So  that  even  the  connexion  of  some  of  the 
bones  is  changed.  Other  difrcrcnces  mij;ht  be  added  :  thus  the 
plane  of  the  condyles  is  somewhat  modified,  and  the  terminal 
edge  of  the  premaxillaries  forms  an  arch.  In  fact,  on  comparison 
with  the  skull  of  a  common  ox,  scarcely  a  single  hone  presents 
the  same  exact  shape,  and  the  whole  skull  has  a  wonderfully 
different  appearance  V 

As  I  cannot  find  that  this  remarkable  skull  has 
been  fi<^ured  before,  I  have  had  the  accompanying 
woodcut  made  in  order  to  compare  it  with  the 
skull  of  a  Charsley  Forest  ox  ;  and  a  glance  is  suffi- 
cient to  show  what  '*  a  wonderfully  different  appear- 
ance "  it  presents. 

Now  the  important  points  in  the  present  connexion 
with  regard  to  this  peculiar  race  of  cattle  are  the 
following. 

Their  origin  is  not  known  ;  but  it  must  have  been 
subsequent  to  the  year  1552,  when  cattle  were  first 
introduced  to  America  from  Europe,  and  it  is  known 
that  such  cattle  have  been  in  existence  for  at  least 
a  century.  The  breed  is  very  true,  and  a  niata  bull 
and  cow  invariably  produce  niata  calves.  A  niata 
bull  crossed  with  a  common  cow,  and  the  reverse 
cross,  yield  oflTspring  having  an  intermediate  character, 
but  with  the  niata  peculiarities  highly  conspicuous  ^. 

Here,  then,  we  have  unquestionable  evidence  of 
a  whole  congeries  of  very  distinctive  characters,  so 
unlike  anything  that  occurs  in  any  other  cattle, 
that,  had  they  been  found  in  a  state  of  nature, 
they    would    have    been    regarded    as    a    distinct 


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*  Darwin,  Variation,  &c.,  vol.  i.  pp.  92-4. 
'  Ibid.  p.  94. 

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194         Danvtn,  and  after  Darwin. 


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species.  And  the  highly  peculiar  characters  which 
they  present  conform  to  all  "the  most  essential 
features  of  specific  characters,"  as  these  are  stated 
by  Mr.  Wallace  in  his  objection  to  the  case  of  the 
pig's  appendages.  That  is  to  say,  "  they  are  sym- 
metrical, they  are  inherited,  and  they  are  constant." 
In  point  of  fact,  they  are  ahvays  "constant,"  both  as 
to  occurrence  and  symmetry,  while  they  are  so 
completely  "inherited  "  that  not  only  does  "a  ni.ata 
bull  and  cow  invariably  produce  niata  calves";  but 
even  when  crossed  with  other  cattle  the  result  is  a 
hybrid^  '•  with  the  niata  character  strongly  displayed." 

Hence,  if  we  were  to  follow  Mr.  Wallace's  criteria 
of  specific  characters,  which  show  that  the  pig's 
appendfi^es  "cannot  be  classed  with  specific  char- 
acters "  (or  with  anything  of  the  nature  of  specific 
characters),  it  would  follow  that  the  niata  peculiarities 
can  be  so  classed.  This,  therefore,  is  a  case  where 
he  will  find  all  the  reasons  which  in  other  cases 
he  takes  to  justify  him  in  falling  back  upon  the 
argument  from  ignorance.  The  cattle  are  half 
wild,  he  may  urge ;  and  so  the  three- fold  con- 
stancy of  their  peculiar  characters  may  very  well 
be  due,  either  directly  or  indirectly,  to  natural 
selection — i.e.  they  may  either  be  of  some  hidden 
use  themselves,  or  correlated  with  some  other  modi- 
fications that  are  of  use :  it  is,  he  may  say,  as  in 
such  cases  he  often  does  say,  for  us  to  disprove  both 
these  possibilities. 

Well,  here  we  have  one  of  those  rare  cases  where 
historical  information,  or  other  accidents,  admit  of 
our  discharging  this  burden  of  proving  a  negative. 
Darwin's  further  description  shows  that  this  custom- 


Characters  as  Adaptive  and  Specific.    195 


ary  refu^'e  in  the  arpiimcnt  from  ignorance  is  most 
cflfcctually  closed.     For — 

"When  the  pasture  is  tolerably  lon<^,  these  cattle  feed  as  well 
as  common  cattle  with  their  tongue  and  palate  ;  but  tlurins  the 
great  droughts,  wlien  so  many  animals  perish  on  the  I'ampas, 
the  niata  breed  lies  under  a  great  dis^idvantage,  and  would, 
if  not  attemltd  to,  become  extinct ;  for  the  common  cattle,  like 
horses,  are  able  to  kctp  alive  l)y  browsing  wiili  their  li[)s  on  the 
twigs  of  trees  ami  on  neds  ;  this  the  nia'as  cannot  so  well  do, 
as  their  lips  do  not  join,  and  hence  tluy  are  found  to  perish 
before  the  conmion  cattle.  This  strike;-,  me  as  a  good  illus- 
tration of  how  little  we  are  able  to  judge  from  the  ordinary 
habits  of  an  animal,  on  what  circumstances,  occurring  only  at 
long  intervals  of  time,  its  rarity  or  extinction  may  depend. 
It  shows  us,  also,  how  natural  selection  would  have  determined 
the  rejection  of  the  niata  niodiiication,  had  it  arisen  in  a  state 
of  nature '." 

Hence,  it  is  plainly  impossible  to  attribute  this 
modification  to  natural  selection,  either  as  acting 
directly  on  the  modified  parts  thi  msclves,  or  indi- 
rectly through  correlation  of  growth.  And  as  the 
modification  is  of  specific  magnitude  on  the  one 
hand,  while  it  presents  all  '"  the  most  essential  fea- 
tures of  specific  characters "  on  the  other,  I  do  not 
see  any  means  whereby  Mr.  Wallace  can  meet  it 
on  his  a  priori  principles.  It  would  be  useless  to 
answer  that  these  characters,  although  conforming  to 
all  his  tests  of  specific  characters,  differ  in  respect 
of  being  deleterious^  and  would  therefore  lead  to  ex- 
termination were  the  animals  in  a  wholly  wild  state ; 
because,  considered  as  an  argument,  this  would  involve 
the  assumption  that,  apart  from  natural  selection, 
only  deleterious   characters   can   arise    under  nature 

'  Darwin,  Variation,  ac.  vol.  i.  p.  94. 
O    2 


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196        Darwin,  and  after  Darwin. 


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— i.  e.  that  merely  "indifferent"  characters  can  never 
do  so,  which  would  be  absurd.  Indeed,  I  have  chosen 
this  case  of  the  niata  cattle  expressly  because  their 
strongly  marked  peculiarities  are  deleterious,  and 
therefore  exclude  Mr.  Wallace's  apptv^l  to  the  argu- 
ment from  ignorance  of  a  possible  utility.  But  if  even 
these  pronounced  and  deleterious  peculiarities  can 
arise  and  be  perpetuated  with  such  constancy  and 
fidelity,  much  more  is  this  likely  to  be  the  case  with 
less  pronounced  and  merely  neutral  peculiarities. 

It  may,  however,  be  further  objected  that  these 
cattle  are  not  improbably  the  result  of  artificial  selec- 
tion. It  may  be  suggested  that  the  semi-monstrous 
breed  originated  in  a  single  congenital  variation,  or 
"  sport,"  'vhich  was  isolated  and  multiplied  as  a 
curiosity  by  the  early  settlers.  But  even  if  such  be  the 
explanation  of  this  particular  case,  the  fact  would 
not  weaken  our  illustration.  On  the  contrary,  it 
would  strengthen  our  general  argument,  by  showing  an 
additional  means  whereby  indifferent  specific  charac- 
ters can  arise  and  become  fixed  in  a  state  of  nature. 
As  it  seems  to  me  extremely  probable  that  the  niata 
cattle  did  originate  in  a  congenital  monstrosity,  which 
was  then  isolated  and  multiplied  by  human  agency 
(as  is  known  to  have  been  the  case  with  the  "  ancon 
sheep"),  I  will  explain  why  this  tends  to  strengthen 
our  general  argument. 

It  is  certain  that  if  these  animals  were  ever  subject 
to  artificial  isolation  for  the  purpose  of  establishing 
their  breed,  the  process  must  have  ceased  a  long  time 
ago,  seeing  that  there  is  no  memory  or  tradition  of 
its  occurrence.  Now  this  proves  that,  however  the 
breed  may  have  originated,  it  has  been  able  to  main- 


^1 


it 


igan 


Characters  as  Adaptive  and  Specific.    197 

tain  its  many  and  highly  pecuh'ar  characters  for  a 
number  of  generations  without  the  help  of  selection, 
either  natural  or  artificial.  This  is  the  first  point  to 
be  clear  upon.  Be  its  origin  what  it  1  ^ay,  we  know 
that  this  breed  has  proved  capable  of  perpetuating 
itself  with  uniform  "constancy"  for  a  number  of 
generations  after  the  artificial  selection  has  ceased — 
supposing  such  a  process  ever  to  have  occurred.  And 
this  certain  fact  that  artificial  selection,  even  if  it 
was  originally  needed  to  establish  the  type,  has  not 
been  needed  to  perpetuate  the  type,  is  a  full  answer 
to  the  supposed  objection.  For,  in  view  of  this  fact,  it 
is  immaterial  what  the  origin  of  the  niata  breed  may 
have  been.  In  the  present  connexion,  the  importance 
of  this  breed  consists  in  its  proving  the  subsequent 
"stability"  of  an  almost  monstrous  form,  continued 
through  a  long  series  of  generations  by  the  force 
of  heredity  alone,  without  the  aid  of  any  form  of 
selection. 

The  next  point  is,  that  not  only  is  a  seeming 
objection  to  the  illustration  thus  removed,  but  that, 
if  we  do  entertain  the  question  of  origin,  and  if  we 
do  suppose  the  origin  of  these  cattle  to  have  been 
in  a  congenital  "  sport."  afterwards  multiplied  by 
artificial  isolation,  we  actually  strengthen  our  general 
argument  by  increasing  the  importance  of  this  par- 
ticular illustration.  For  the  illustration  then  becomes 
available  to  show  how  indifferent  specific  characters 
may  sometimes  originate  in  merely  individual  sports, 
which,  if  not  immediately  extinguished  by  free 
intercrossing,  will  perpetuate  themselves  by  the 
unaided  force  of  heredity.  But  this  is  a  point  to  which 
we  shall  recur  in  the  ensuing  chapter. 


11 


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I 

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198         Darwirij  and  after  Darwin, 


If..     ■  .,f.1l., 

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ll^'J)     :| 


III 


In  conclusion,  it  is  worth  while  to  remark,  with 
regard  to  Mr.  Wallace's  argument  from  constancy, 
that,  as  a  matter  of  fact,  utility  does  not  seem  to 
present  any  greater  power  in  securing  "  stability  of 
characters"  than  any  other  cause  of  like  constancy. 
Thus,  for  instance,  whatever  the  causes  may  have 
been  which  have  produced  and  perpetuated  the  niata 
breed  of  cattle,  they  have  certainly  produced  a  w  on- 
derful  ''  stability  "  of  a  great  modification  in  a  wonder- 
fully short  time.  And  the  same  has  to  be  said  of  the 
ducks  in  St.  James'  Park,  as  well  as  sundry  other  cases. 
On  the  other  hand,  when,  as  in  the  case  of  numberless 
natural  species,  modification  has  been  undoubtedly 
produced  by  natural  selection,  although  the  modifica- 
tion must  have  had  a  very  much  longer  time  in  which 
to  have  been  fixed  by  heredity,  it  is  often  far  from 
being  stable — ^notwithstanding  that  Mr.  Wallace 
regards  stability  as  a  criterion  of  specific  characters. 
Indeed — and  this  is  more  suggestive  still — there  even 
seems  to  be  a  kind  of  inverse  proportion  between  the 
utility  and  the  stability  of  a  specific  character.  The  ex- 
planation appears  to  be  ( Origin  of  Species^  pp.  1 20-1), 
that  the  more  a  specific  character  has  been  forced  on 
by  natural  selection  on  account  of  its  utility,  the  less 
time  will  it  have  had  to  become  well  fixed  by  heredity 
before  attaining  a  full  development.  Moreover,  as 
Darwin  adds,  in  cases  where  the  modification  has 
not  only  been  thus  "  comparatively  recent,''  but  also 
'*  extraordinarily  great,"  the  probability  is  that  the 
parts  so  modified  must  have  been  very  variable  in  the 
first  instance,  and  so  are  all  the  more  difficult  to 
render  constant  by  heredity.  Thus  we  see  that  utility 
is   no    better — even   if   it   be   so   good — a   cause   of 


!!: 


Characters  as  Adaptive  and  Specific.    199 

stability  in  specific  characters,  as  are   the  unknown 
causes  of  stability  in  many  varietal  characters  ^. 

^  Should  it  be  objected  that  useless  characters,  according  to  my  own 
view  of  the  Cessation  of  Selection,  ought  to  disappear,  and  therefore 
cannot  be  constant,  the  answer  is  evident.  For,  by  hypothesis,  it  is  only 
those  useless  characters  which  were  at  one  time  useful  that  disappear 
under  this  principle.  Selection  cannot  cease  unless  it  was  previously  present 
— i.e.  save  in  cases  where  the  now  useless  character  was  originally  duo 
to  selection.  Hence,  in  all  cases  where  it  was  due  to  any  other  cause,  the 
useless  character  will  persist  at  least  as  long  as  its  originating  cause 
continues  to  operate.  And  even  after  the  latter  (whatever  it  may  be) 
has  ceased  to  operate,  the  useless  character  will  but  slowly  degenerate, 
until  the  eventual  failure  of  heredity  causes  it  to  disappear  in  toto — long 
before  which  time  it  may  very  well  have  become  a  generic,  or  some  higher, 
character. 


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CHAPTER   VIII. 

Characters  as  Adaptive  and  Specific 

{continued). 

Let  us  now  proceed  to  indicate  some  of  the 
causes,  other  than  natural  selection,  which  may  be 
regarded  as  adequate  to  induce  such  changes  in 
organic  types  as  are  taken  by  systematists  to  con- 
stitute diagnostic  distinctions  between  species  and 
species.  We  will  first  consider  causes  external  to 
organisms,  and  will  then  go  on  to  consider  those  which 
occur  within  the  organisms  themselves :  following,  in 
fact,  the  classification  which  Darwin  has  himself  laid 
down.  For  he  constantly  speaks  of  such  causes  as 
arising  on  the  one  hand,  from  'charged  conditions  of 
life  "  and,  on  the  other  hand,  from  '*  the  nature  of  the 
organism  " — that  is,  from  internal  processes  leading 
to  variations  which  seem  to  us  in  our  ignorance  to 
arise  spontaneously." 

In  neither  case  will  it  be  practicable  to  give  more 
than  a  brief  restifn^  of  all  that  might  be  said  on  these 
interesting  topics. 

I.  Climate. 

Theie  is  an  overwhelming  mass  of  evidence  to 
prove  that  the  aremblage  of  external  conditions  of 
life  conveniently  summarized   in  the  word  Climate, 


i 


i 


Characters  as  Adaptive  and  Specific.    201 

exercise  a  potent,  an  uniform,  and  a  permanent  in- 
fluence on  specific  characters. 

With  regard  to  plants,  Darwin  adduces  a  number 
of  facts  to  show  the  effects  of  climate  on  wheat, 
cabbages,  and  other  vegetables.  Here,  for  example, 
is  what  he  says  with  regard  to  maize  imported 
from  America  to  Germany  : — 

*'  During  the  first  year  the  plants  were  twelve  feet  high,  and 
a  few  seeds  were  perfected  ;  the  lower  seeds  in  the  ear  kept 
true  to  their  proper  form,  but  the  upper  seeds  became  slightly 
changed.  In  the  second  generation  the  plants  were  from  nine 
to  ten  feet  high,  and  ripened  their  seed  better ;  the  depressir  • 
on  the  outer  side  of  the  seed  had  almost  disappeared,  and  the 
original  beautiful  white  colour  had  become  duskier.  Some 
of  the  seeds  had  even  become  yellow,  and  in  their  now  rounded 
form  they  approached  the  common  European  maize.  In  the 
third  generation  nearly  all  resemblance  to  the  original  and  very 
distinct  American  parent-form  was  lost '." 

As  these  "  highly  remarkable  "  changes  were  effected 
in  but  three  generations,  it  is  obvious  that  they 
cannot  have  been  dependent  on  selection  of  any 
kind.    The  same  remark  applies  to  trees.    Thus, — 

"  Mr.  Meehan  has  compared  twenty-nine  kinds  of  American 
trees  with  their  nearest  ILuropean  allies,  all  grown  in  close 
proximity  and  under  as  nearly  as  possible  the  same  conditions. 
In  the  American  species  he  finds,  with  the  rarest  exceptions, 
that  the  leaves  fall  earlier  in  the  season,  and  assume  before  their 
fall  a  brighter  tint ;  that  they  are  less  deeply  toothed  or  serrated  ; 
that  the  buds  are  smaller;  that  the  trees  are  more  diffuse  in 
growth  and  have  fewer  branchlets ;  and,  lastly,  that  the  seeds 
are  smaller — all  in  comparison  with  the  corresponding  European 
species.      Now,  considering    that    these    corresponding    trees 

*  Variation,  &c.  vol.  i.  p.  340. 


II 


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202        Darwin,  and  after  Darwin, 

belong  to  several  distinct  orders,  and  that  they  are  adapted  to 
widely  different  stations,  it  can  hardly  be  supposed  that  theii 
differences  are  of  any  special  service  to  them  in  the  New  and 
Old  worlds  ;  and,  if  so,  such  differences  cannot  have  been  gained 
through  natural  selection,  and  must  be  attributed  to  the  long 
continued  action  of  a  different  climate*." 


These  cases,  however,  I  quote  mainly  in  order  to 
show  Darwin's  opinion  upon  the  matter,  with  reference 
to  the  absence  of  natural  selection.  For,  where  the 
vegetable  kingdom  is  concerned,  the  fact  of  climatic 
variation  is  so  general,  and  in  its  relation  to  diag- 
nostic work  so  important,  that  it  constitutes  one  of 
the  chief  difficulties  against  which  species-makers 
have  to  contend.  Ana  the  more  carefully  the  subject 
is  exammed  the  greater  does  the  difficulty  become. 
But.  as  to  this  and  other  general  facts,  it  will  be 
best  to  allow  a  recognized  authority  to  speak ;  and 
therefore  I  will  give  a  few  extracts  from  Kerner's 
work  on  Gute  und  schlechte  Arten. 

He  begins  by  showing  that  geographical  (or  it 
may  be  topographical)  varieties  of  species  are  often 
so  divergent,  that  without  a  knowledge  of  intermediate 
forms  there  could  be  no  question  as  to  their  being 
good  species.  As  a  result  of  his  own  researches  on 
the  subject,  he  can  scarcely  find  language  strong 
enough  to  express  his  estimate  of  the  extent  and 
the  generality  of  this  source  of  error.  In  different 
parts  of  Europe,  or  even  in  different  parts  of  the 
Alps,  he  has  found  these  climatic  varieties  in  such 
multitudes  and  in  such  high  degrees  both  of  con- 
stancy and  divergence,  that,  after  detailing  his  results, 

*  Variation^  &c.  vol.  ii.  p.  271. 


Characters  as  Adaptive  and  Specific.    203 

he  finishes  his  essay  with  the  following  remarkable 
conclusions : — 


"  Die  Wissenchaft  geht  aber  ihren  i^ntwicklungsgang  im 
grossen  Ganzen  gerade  so,  wie  die  Erkenniniss  bei  jedem  einzel- 
nen  Naturforscher.  F^ast  jcder  liotaniker  muss  seinen  Entwick- 
lungsgang  durchmachen  und  gciangt  endlich  melir  oder  weniger 
nahe  zu  demselben  Ziele.  Die  Ungleichheit  besteht  nur  darin, 
dass  der  eine  langsamer,  der  andere  aber  rascher  bei  dem  Ziele 
ankommt.  Anfanglich  miiht  sich  jeder  ab,  die  Formen  in 
hergebruchter  Weise  zu  gliedern  und  die  *guten  Arten '  herauszu- 
lesen.  Mit  der  Erweiterung  lics  Gesichtskreises  und  niit  der 
Vermehrung  der  Anschauungen  aber  schvvindet  auch  immer 
mehr  der  IJoden  unter  den  Fussen,  die  bishcr  fiir  unverriickbar 
gehaltenen  Grenzen  der  gut  gcfjlaubten  Arten  stellen  sich  als 
eine  der  Natur  angelegte  Zwangsjacke  heraus,  die  Ueberzeugung, 
dass  die  Grenzen,  welche  wir  ziehen,  eben  nur  kiinstliche  sind, 
gewinnt  immer  mehr  und  mehr  die  Oberhand,  und  wer  nicht 
gerade  zu  den  hartgesottenen  Eigensinnigen  gehort,  und  wer 
die  Wahrheit  hoher  stellt  als  das  starre  Festhaltcn  an  seinen 
friiheren  Ansichten,  geht  schiiessUch  bewusst  oder  unbewusst 
in  das  Lager  derjenigen  iiber,  in  welchem  auch  ich  mir  ein 
bescheidenes  Platzchen  aufgesucht  habe." 

By  these  "hard-boiled"  botanists  he  means  those 
who  entertain  the  traditional  notion  of  a  species  as 
an  assemblage  of  definite  characters,  always  and 
everywhere  associated  together.  This  notion  (Arts- 
bestandigkeit)  must  be  entirely  abandoned.  Sum- 
marizing Kerner^s  facts  for  their  general  results  we  find 
that  his  extensive  investigations  have  proved  that  in 
his  numberless  kinds  of  European  plants  the  following 
relations  frequently  obtain.  Supposing  th?t  there  are 
two  or  more  allied  species,  A  and  B,  then  A'  and  B' 
may  be  taken  to  represent  their  respective  types  as 
found  in  some  particular  area.     It   does  not  signify 


II 

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1.1 


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204         Darzvin,  and  after  Darwin, 


■"V 


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1,1 


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whether  A'  and  B'  are  geographically  remote  from, 
or  close  to,  A  and  B ;  the  point  is  that,  whether  in 
respect  of  temperature,  altitude,  moisture,  character 
of  soil,  &c.,  there  is  some  difference  in  the  conditions 
of  life  experienced  by  the  plants  growing  at  the  dif- 
ferent places.  Now,  in  numberless  plants  it  is  found 
that  the  typical  or  constant  peculiarities  of  A'  differ 
more  from  those  of  A  than  they  do  from  those  of  B ; 
while,  conversely,  the  characters  of  A'  may  bear  more 
resemblance  to  those  of  B'  than  they  do  to  those 
of  A — on  account  of  such  characters  being  due  to 
the  same  external  causes  in  both  cases.  The  conse- 
quence is  that  A'  might  more  correctly  be  classified 
with  B',  or  vice  versa.  Another  consequence  is  that 
whether  A  and  B,  or  A'  and  B',  be  recorded  as  the 
"  good  species "  usually  depends  upon  which  has 
happened  to  have  been  first  described. 

Such  a  mere  abstract  of  Kerner's  general  results, 
however,  can  give  no  adequate  idea  of  their  cogency : 
for  this  arises  from  the  number  of  species  in  which 
specific  characters  are  thus  found  to  change,  and  even  to 
interchange,  with  different  conditions  of  life.  Thus  he 
gives  an  amusing  parable  of  an  ardent  young  botanist, 
Simplicius,  who  starts  on  a  tour  in  the  Tyrol  with 
the  works  of  the  most  authoritative  systematists  to 
assist  him  in  his  study  of  the  flora.  The  result  is 
that  Simplicius  becomes  so  hopelessly  bewildered  in 
his  attempts  at  squaring  their  diagnostic  descriptions 
with  the  facts  of  nature,  that  he  can  only  exclaim 
in  despair — "  Sonderbare  Flora,  diese  tirolische,  in 
welcher  so  viele  characteristische  Pflanzen  nur 
schlechte  Arten,  oder  gar  noch  schlechter  als  schlechte 
Arten,  sind."     Now,   in   giving   illustrations   of    this 


Characters  as  Adaptive  and  Specific.    205 

young  man's  troubles,  Kerner  fills  five  or  six  pages 
with  little  else  than  rows  of  specific  names. 

Upon  the  whole,  Kerner  concludes  that  the  more 
the  subject  is  studied,  the  more  convinced  must  the 
student  become  that  all  distinction  between  species  as 
" good "  and  " bad "  vanishes.  In  other  words,  the  more 
that  our  knowledge  of  species  and  of  their  diagnostic 
characters  increases,  the  more  do  we  find  that  '•  bad 
species"  multiply  at  the  expense  of  "  good  species"  ;  so 
that  eventually  we  must  relinquish  the  idea  of  "  good 
species  "  altogether.  Or,  conversely  stated,  we  must 
agree  to  regard  as  equally  "  good  species "  any  and 
every  assemblage  of  individuals  which  present  the 
same  peculiarities :  provided  that  these  peculiarities 
do  not  rise  to  a  generic  value,  they  equally  deserve 
to  be  regarded  as  "'specific  characters,"  no  matter 
how  trivial,  or  how  local,  they  may  be.  In  fact,  he 
goes  so  far  as  to  say  that  when,  as  a  result  of 
experiments  in  transplantation  from  one  set  of 
physical  conditions  to  another,  seedlings  are  found 
to  present  any  considerable  and  constant  change  in 
their  specific  characters,  these  seedlings  are  no  less 
entitled  to  be  regarded  as  a  'good  species"  than 
are  the  plants  from  which  they  have  been  derived. 
Probably  few  systematists  will  consent  to  go  quite 
so  far  as  this ;  but  the  fact  that  Kerner  has  been 
led  deliberately  to  propound  such  a  statement  as 
a  result  of  his  wide  observations  and  experiments 
is  about  as  good  evidence  as  possible  on  the 
points  with  which  we  are  here  concerned.  For  even 
Simplicius  would  hardly  be  quite  so  simple  as  to 
suppose  that  each  one  of  all  the  characters  which 
he   observes   in   his   "  remarkable   flora,"   so   largely 


:i 

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■  '•  f,i 


2o6         Darwifiy  and  after  Darwin. 


;■;* 


composed  of  "bad  or  even  worse  than  bad  species," 
is  of  utilitarian  significance. 

Be  it  noted,  however,  that  I  am  not  now  ex- 
pressing my  own  opinion.  There  are  weighty  reasons 
against  thus  identifying  climatic  variations  with 
good  species — reasons  which  will  be  dealt  with 
in  the  next  chapter.  Kern'--  does  not  seem  to 
appreciate  the  weight  of  these  reasons,  and  therefore 
I  do  not  call  him  as  a  witness  to  the  subject  as 
a  whole ;  but  only  to  that  part  of  it  which  has  to  do 
with  the  great  and  general  importance  of  climatic 
variability  in  relation  to  diagnostic  work.  And  thus 
far  his  testimony  is  fully  corroborated  by  every  other 
botanist  who  has  ever  attended  to  the  subject. 
Therefore  it  does  not  seem  worth  while  to  quote 
further  authorities  in  substantiation  of  this  point,  such 
as  Gartner.  De  CandoUe.  Nageli,  Peter,  Jordan,  &c- 
For  nowadays  no  one  will  dispute  the  high  generality 
and  the  frequently  great  extent  of  climatic  variation 
where  the  vegetable  kingdom  is  concerned.  Indeed, 
it  may  fairly  be  doubted  whether  there  is  any  one 
species  of  plant,  whose  distribution  exposes  it  to  any 
considerable  differences  in  its  external  conditions  of 
life,  which  does  not  present  more  or  less  considerable 
differences  as  to  its  characters  in  different  parts  of  its 
range.  The  principal  causes  of  such  climatic  variation 
appear  to  be  the  chemical,  and.  still  more,  the 
mechanical  nature  of  soil  ;  temperature  ;  intensity  and 
diurnal  duration  of  light  in  spring  and  summer; 
moisture  ;  presence  of  certain  salts  in  the  air  and  soil 
of  marine  plants,  or  of  plants  growing  near  mineral 
springs  ;  and  sundry  other  circumstances  of  a  more 
or  less  unknown  character. 


Characters  as  Adaptive  and  Specific.    207 


»i 


Before  closing  these  remarks  on  climatic  variation  in 
the  vegetable  kingdom,  prominent  attention  must  be 
directed  to  a  fact  of  broad  generality  and,  in  relation 
to  our  present  subject,  of  considerable  importance. 
This  is  that  the  same  external  causes  very  frc(iuently 
produce  the  same  effects  in  the  way  of  specific  change 
throughout  large  numbers  of  unrelated  species-  i.  e. 
species  belonging  to  different  genera,  families,  and 
orders.  Moreover,  throughout  all  these  unrelated 
species,  we  can  frequently  trace  a  uniform  correlation 
between  the  degrees  of  change  and  the  degrees  to 
which  they  have  been  subjected  to  the  causes  in 
question. 

As  examples,  all  botanists  who  have  attended  to 
the  subject  are  struck  by  the  similarity  of  variation 
presented  by  different  species  growing  on  the  same 
soils,  altitudes,  latitudes,  longitudes,  and  .so  forth. 
Plants  growing  on  chalky  soils,  vvhen  compared  with 
those  growing  on  richer  soils,  are  often  more  thickly 
covered  with  down,  which  is  usually  of  a  white  or 
grey  colour.  Their  leaves  are  frequently  of  a  bluish- 
green  tint,  more  deeply  cut.  and  less  veined,  while 
their  flowers  tend  to  be  larger  and  of  a  lighter 
tint.  There  are  similarly  constant  differences  in 
other  respects  in  varieties  growing  on  sundry  other 
kinds  of  soils.  Sea-salt  has  the  general  effect,  on 
many  different  kinds  of  plants,  of  producing  moist 
fleshy  leaves,  and  red  tints.  Experiments  in  trans- 
plantation have  shown  that  these  changes  may  be 
induced  artificially  ;  so  there  can  be  no  doubt  as  to  its 
being  this  that  and  the  other  set  of  external  conditions 
which  produces  them  in  nature.  Again,  dampness 
causes  leaves  to  become  smoother,  greener,  less  cut, 


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and  the  flowers  to  become  darker ;  while  dryness 
tends  to  produce  opposite  eficcts.  I  need  not  go  on 
to  specify  the  particular  results  on  all  kinds  of  plants 
of  altitude,  latitude,  lonj^jitude,  and  so  forth.  For  we 
arc  concerned  only  with  the  fact  that  these  two 
correlations  m.-iy  be  regarded  as  general  laws  apper- 
taining to  the  vegetable  kingdom — namely,  (A)  that 
the  same  external  causes  produce  similar  varietal 
effects  in  numerous  unallied  species  of  plants ;  and. 
(B)  that  the  more  these  species  are  exposed  to  such 
causes  the  greater  is  the  amount  of  varietal  effect 
produced  -  so  that,  for  instance,  on  travelling  from 
latitude  to  latitude,  longitude  to  longitude,  altitude 
to  altitude,  &c.,  we  may  see  greater  and  greater 
degrees  of  such  definite  and  more  or  less  common 
varietal  changes  affecting  the  unallied  species  in 
question.  Now  those  general  laws  are  of  importance 
for  us,  because  they  prove  unequivocally  that  it  is  the 
direct  action  of  external  conditions  of  life  which 
produce  climatic  variations  of  specific  types.  And, 
taken  in  connexion  with  the  lesults  of  experiments  in 
transplantation  (which  in  a  single  generation  may 
yield  variations  similar  to  those  found  in  nature  under 
similar  circumstances),  these  general  laws  still  further 
indicate  that  climatic  variations  are  "  indifferent " 
variations.  In  other  words,  we  find  that  changes  of 
specific  characters  are  of  widespread  occurrence  in  the 
vegetable  kingdom,  that  they  are  con.stantly  and  even 
proportionally  related  to  definiteexternal  circumstances, 
but  yet  that,  in  as  far  as  they  are  climatic,  they  can- 
not be  attributed  to  the  agency  of  natural  selection'. 

'  Since  the  above  paragraphs  hare  been  in  type,  the  Rev.  G.  Henslow 
has  published  his  Linnaean  Society  papers  which  are  mentioned  in  the 


Characters  as  Adaptive  and  Spccijic.    209 


i 


Turning  next  to  animals,  it  may  first  be  observed 
that  climatic  conditions  do  not  appear  to  exercise 
an  influence  either  so  fjcncral  or  so  considerable 
as  in  the  case  of  plants.  Nevertheless,  althou<;h 
these  influences  are  relatively  more  effective  in  tlie 
vegetable  kingdom  than  they  are  in  the  animal, 
absolutely  considered  they  are  of  high  generality  and 
great  importance  even  in  the  latter.  Hut  as  this 
fact  is  so  well  recognized  by  all  zoologists,  it  will 
be  needless  to  give  more  than  a  very  few  illustrations. 
Indeed,  throughout  this  discussion  on  climatic  in- 
fluences my  aim  is  merely  to  give  the  general  reader 
some  idea  of  their  importance  in  regard  to  system- 
atic natural  history ;  and,  therefore,  such  particular 
cases  as  are  mentioned  are  selected  only  as  samples 
of  whole  groups  of  cases  more  or  less  similar. 

With  regard  to  animals,  then,  we  may  best  begin 
by  noticing  that,  just  as  in  the  case  of  plants,  there  is 
good  evidence  of  the  same  external  causes  prodiicing 
the  same  effects  in  multitudes  of  species  belonging 
to  different  genera,  families,  orders,  and  even  classes. 
Moreover,  we  are  not  without  similarly  good  evidence 
of  degrees  of  specific  change  taking  place  in  correlation 
with  degrees  of  climatic  change,  so  that  we  may 
frequently  trace  a  gradual  progress  of  the  former  as 
we  advance,  say,  from  one  part  of  a  large  continent 
to  another.  Instances  of  thes^  correlations  are 
not  indeed  so  numerous  in  the  animal  kingdom  as 
they  are  in  the  vegetable.  Nevertheless  they  are 
amply  sufficient  for  our  present  purposes. 

For   example,    Mr.    Allen    has   studied    in    detail 

introductory  chapter,  and  which  rlcal  in  more  detail  with  this  subject, 
especially  as  regards  the  fades  of  desert  floras. 

II.  P 


I 

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I 

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Pi 


2IO        Darwin,  and  after  Darwin. 


['I  •»«» 

"51^      '"1' 


'^*; 


M'H 


^ 


changes  of  size  and  colour  among  birds  and  mammals 
on  the  American  continent ;  and  he  finds  a  won- 
derfully close  sliding  scale  of  both,  corresponding 
stage  by  stage  with  gradual  changes  of  climate. 
Very  reasonably  he  attributes  this  to  the  direct 
influence  of  climatic  conditions,  without  reference 
to  natural  selection — as  does  also  Mr.  Gould  with 
reference  to  similar  facts  which  he  has  observed 
among  the  birds  of  Australia.  Against  this  view 
Mr.  Wallace  urges,  **  that  the  effects  are  due  to  the 
greater  or  less  need  of  protection."  But  it  is  difficult 
to  believe  that  such  can  be  the  case  where  so  in- 
numerable a  multitude  of  widely  different  species 
are  concerned — presenting  so  many  diverse  habits, 
as  well  as  so  many  distinct  habitats.  Moreover,  the 
explanation  seems  incompatible  with  the  graduated 
nature  of  the  change,  and  also  with  the  fact  that  not 
only  colouration  but  size,  is  implicated. 

We  meet  with  analogous  facts  in  butterflies. 
Thus  Lycaena  agestis  not  only  presents  seasonal 
variations,  (A)  and  (B);  but  while  (A)  and  (B)  are 
respectively  the  winter  and  summer  forms  in 
Germany,  (B)  and  (C)  are  the  corresponding  forms 
in  Italy.  Therefore,  (B)  is  in  Germany  the  summer 
form,  and  in  Italy  the  winter  form — the  German 
winter  form  (A)  being  absent  in  Italy,  while  the 
Italian  summer  form  (C)  is  absent  in  Germany. 
Probably  these  facts  are  due  to  differences  of  tem- 
perature in  the  two  countries,  for  experiments  have 
shown  that  when  pupae  of  sundry  species  of  moths 
and  butterflies  are  exposed  to  different  degrees  of 
temperature,  the  most  wonderful  changes  of  colour 
may  result   in  the  insects  which  emerge.     The   re- 


lr< 


Characters  as  Adaptive  and  Specific.    211 

markable  experiments  of  Dorfmeister  and  Weismann 
in  relation  to  this  subject  are  well  known.  More 
recently  Mr.  Merrifield  has  added  to  their  facts,  and 
concludes  that  the  action  of  cold  upon  the  pupae — 
and  also,  apparently,  upon  the  larvae— has  a  tendency 
to  produce  dark  hues  in  the  perfect  insect  ^ 

But,  passing  now  from  such  facts  of  climatic  vari- 
ations over  wide  areas  to  similar  facts  within  small 
areas,  in  an  important  Memoir  on  the  Cave  Fauna 
of  North  America^  published  a  few  years  ago  by  the 
American  Academy  of  Sciences,  it  is  stated : — 

"As  regards  change  of  colour,  we  do  not  recall  an  exception  to 
the  general  rule  that  all  cave  animals  are  either  colourless  or 
nearly  white,  or,  as  in  the  case  of  Arachnida  and  Insects,  much 
paler  than  their  out-of-door  relatives." 

Now,  when  we  remember  that  these  cave  faunas 
comprise  representatives  of  nearly  all  classes  of  the 
animal  kingdom,  it  becomes  difficult,  if  not  impos- 
sible, to  imagine  that  so  universal  a  discharge  of 
colouring  can  be  due  to  natural  selection.  It  must 
be  admitted  that  the  only  way  in  which  natural 
selection  could  act  in  this  case  would  be  indirectly 
through  the  principle  of  correlation.  There  being  no 
light  in  the  caves,  it  can  be  of  no  advantage  to  the 
animals  concerned  that  they  should  lose  their  colour 
for  the  sake  of  protection,  or  for  any  other  reason  of 
a  similarly  direct  kind.  Therefore,  if  the  loss  of  colour 
is  to  be  ascribed  to  natural  selection,  this  can  only 
be  done  by  supposing  that  natural  selection  has  here 
acted  indirectly  through  the  principle  of  correlation. 
There  is  evidence  to  show  that  elsewhere  modification 


m 


H 


'4       , 


H 


'  '1; 


'  Trans.  Entom.  Soc.  1889,  part  i.  p.  79  et  seg, 

P   2 


2i2 


Darwifif  and  after  Darwin, 


M. 


I.  ■) 


?»»■ 


I*.: 


;  ! 


or  loss  of  colour  is  in  some  cases  brought  about  by 
natural  selection,  on  account  of  the  original  colour 
being  correlated  with  certain  physiological  characters 
(such  as  liability  to  particular  diseases,  &c.) ;  so  that 
when  natural  selection  operates  directly  upon  these 
physiological  characters,  it  thereby  also  operates 
indirectly  upon  the  correlated  colouis.  But  to  suppose 
that  this  can  be  the  explanation  of  the  uniform 
diminution  of  colour  in  all  inhabitants  of  dark  caves 
would  be  manifestly  absurd.  If  there  were  only  one 
class  of  animals  in  these  caves,  such  as  Insects,  it 
might  be  possible  to  surmise  that  their  change  of 
colour  is  due  to  natural  selection  acting  directly  upon 
their  physiological  constitutions,  and  so  indirectly 
upon  their  colours.  But  it  would  be  absurd  to 
suppose  that  such  can  be  the  explanation  of  the 
facts,  when  these  extend  in  so  similar  a  manner  over 
so  many  scores  of  species  belonging  to  such  different 
types  of  animal  life. 

With  more  plausibility  it  might  be  held  that  the 
universal  discharge  of  colour  in  these  cave-faunas 
is  due,  not  to  the  presence,  but  to  the  absence  of 
selection-  i.e.  tc  the  cessation  of  selection,  or  pan- 
mixia. But  against  this — at  all  events  as  a  full  or 
general  explanation — lie  the  following  facts.  First, 
in  the  case  of  Proteus — which  has  often  been  kept 
for  the  purposes  of  exhibition  &c.,  in  tanks — the  skin 
becomes  dark  when  the  animal  is  removed  from  the 
cave  and  kept  in  the  light.  Secondly,  deep-sea  faunas, 
though  as  much  exposed  as  the  cave-faunas,  to  the 
condition  of  darkness,  are  not  by  any  means  invariably 
colourless.  On  the  contrary,  they  frequently  present 
brilliant  colouration.     Thus  it  is  evident  that  if  pan- 


m 


Characters  as  Adaptive  and  Specific.    213 

mixia  be  suggested  in  explanation  of  the  discharge 
of  colouring  in  cave-faunas,  the  continuance  of  colour 
in  deep-sea  faunas  appears  to  show  the  explanation 
insufficient.  Thirdly,  according  to  my  view  of  the 
action  of  panmixia  as  previously  explained,  no  total 
discharge  of  colouration  is  likely  to  be  caused  by  such 
action  alone.  At  most  the  bleaching  as  a  result 
of  the  mere  withdrawal  of  selection  would  proceed 
only  to  some  comparatively  small  extent.  Fourthly, 
Mr.  Packard  in  the  elaborate  Memoir  on  Cave 
Fauna^  already  alluded  to,  states  that  in  some  of 
the  cases  the  phenomena  of  bleaching  appear  to  have 
been  induced  within  very  recent  times — if  not,  indeed, 
within  the  limits  of  a  single  generation.  Should 
the  evidence  in  support  of  this  opinion  prove  trust- 
worthy, of  course  in  itself  it  disposes  of  any  sugges- 
tion either  of  the  presence  or  the  absence  of  natural 
selection  as  concerned  in  the  process. 

Nevertheless,  I  myself  think  it  inevitable  that  to 
some  extent  the  cessation  of  selection  must  have 
helped  in  discharging  the  colour  of  cave  faunas; 
although  for  the  reasons  now  given  it  appears  to  me 
that  the  main  causes  of  change  must  have  been  of 
that  direct  order  which  we  understand  by  the  term 
climatic. 

As  regards  dogs,  the  Rev.  E.  Everest  found  it  impos- 
sible to  breed  Scotch  setters  in  India  true  to  their  type. 
Even  in  the  second  generation  no  single  young  dog 
resembled  its  parents  either  in  form  or  shape.  "  Their 
nostrils  were  more  contracted,  their  noses  more  pointed, 
their  size  inferior,  and  their  limbs  more  slender*." 
Similarly  on  the  coast  of  New  Guinea,  Bosman  says 
^  Variation^  (&c.  vol.  i.  p.  40. 


i 


I   ; 


'  <\ 


214         Darwifiy  and  after  Darwin, 


I.  •*..       T    II 


\ 


iiin 


that  imported  breeds  of  dogs  '*  alter  strangely ;  their 
ears  grow  long  and  stiff  like  those  of  foxes,  to  which 
colour  they  also  incline  .  .  .  and  in  three  or  four 
broods  their  barking  turns  into  a  howl  *." 

Darwin  gives  numerous  facts  sho'ving  the  effects  of 
climate  on  horses,  cattle,  and  sheep,  in  altering,  more 
or  less  considerably,  the  characters  of  their  ancestral 
stocks.  He  also  gives  the  following  remarkable  case 
with  regard  to  the  rabbit.  Early  in  the  fifteenth 
century  a  common  rabbit  and  her  young  ones  were 
turned  out  on  the  island  of  Porto  Santo,  near  Madeira. 
The  feral  progeny  now  differ  in  many  respects  from 
their  parent  stock.  They  are  only  about  one-third  of 
the  weight,  present  many  differences  in  the  relative 
sizes  of  different  parts,  and  have  greatly  changed  in 
colour.  In  particular,  the  black  on  the  upper  surface 
of  the  tail  and  tips  of  the  ears,  which  is  so  constant 
in  all  other  wild  rabbits  of  the  world  as  to  be  given 
in  most  works  as  a  specific  character,  has  entirely 
disappeared.  Again,  "  the  throat  and  certain  parts  of 
the  under  surface,  instead  of  being  pure  white,  are 
generally  grey  or  leaden  colour/'  while  the  upper 
surface  of  the  whole  body  is  redder  than  in  the 
common  rabbit.  Now,  what  answer  have  our  op- 
ponents to  make  to  such  a  case  as  this  ?  Presumably 
they  will  answer  that  the  case  simply  proves  the 
action  of  natural  selection  during  the  best  part  of  400 
years  on  an  isolated  section  of  a  species.  Although 
v/e  cannot  say  of  what  use  all  these  changes  have 
been  to  the  rabbits  presenting  them,  nevertheless  we 
must  believe  that  they  have  been  produced  by  natural 
selection,  and  therefore  must  present  some  hidden  use 
'   Variation^  &c.  vol.  i.  p.  40. 


i 


Characters  as  Adaptive  and  Specific.    215 


I 


to  the  isolated  colony  of  rabbits  thus  peculiarly 
situated.  Four  centuries  is  long  enough  to  admit  of 
natural  selection  effecting  all  these  changes  in  the  case 
of  so  rapidly  breeding  an  animal  as  the  rabbit,  and  there- 
fore it  is  needless  to  look  further  for  any  explanation 
of  the  facts.  Such,  I  say,  is  presumably  the  answer 
that  would  be  given  by  the  upholders  of  natural 
selection  as  the  only  possible  cause  of  specific  change. 
But  now,  in  this  particular  case  it  so  happens  that 
the  answer  admits  of  being  conclusively  negatived, 
by  showing  that  the  great  assumption  on  which  it 
reposes  is  demonstrably  false.  For  Darwin  examined 
two  living  specimens  of  these  rabbits  which  had 
recently  been  sent  from  Porto  Santo  to  the  Zoo- 
logical Gardens,  and  found  them  coloured  as  just 
described.  Four  years  afterwards  the  dead  body 
of  one  of  them  was  sent  to  him,  and  then  he  found 
that  the  following  changes  had  taken  place.  "  The  ears 
were  plainly  edged,  and  the  upper  surface  of  the  tail 
was  covered  with  blackish-grey  fur,  and  the  whole 
body  was  much  less  red ;  so  that  under  the  English 
climate  this  individual  rabbit  has  recovered  the  proper 
colour  of  its  fur  in  rather  less  than  four  years  I  " 

Mr.  Darwin  adds  : — 

"If  the  history  of  these  Porto  Santo  rabbits  had  not  been 
known,  most  naturalists,  on  observing  their  much  reduced  size, 
their  colour,  reddish  above  and  grey  beneath,  their  tails  and 
ears  not  tipped  with  black,  would  have  ranked  them  as  a 
distinct  species.  They  would  have  been  strongly  confirmed  in 
this  view  by  seeing  them  alive  in  the  Zoological  Gardens,  and 
hearing  that  they  refused  to  couple  with  other  rabbits.  Yet  this 
rabbit,  which  there  can  be  little  doubt  would  thus  have  been 
ranked  as  a  distinct  species,  as  certainly  originated  since  the 
year  1420  ^ 

*  Variation,  &c.  vol.  i.  p.  laa 


\M\ 


2i6        Darwin,  ami  after  Darwin, 


N 


(i  ^^ 


^        :'!■■' It 


Moreover,  it  certainly  originated  as  a  direct  result 
of  climatic  influences,  independent  of  natural  selection  ; 
seeing  that,  as  soon  as  individual  members  of  this 
apparently  new  species  were  restored  to  their  original 
climate,  they  recovered  their  original  colouration. 

As  previously  remarked,  it  is,  from  the  nature 
of  the  case,  an  exceedingly  difficult  thing  to  prove 
in  any  given  instance  that  natuial  selection  has  not 
been  the  cause  of  specific  change,  and  so  finally  to 
disprove  the  assumption  that  it  must  have  been. 
Here,  however,  on  account  of  historical  information, 
we  have  a  crucial  test  of  the  validity  of  this  assump- 
tion, just  as  we  had  in  the  case  of  the  niata  cattle; 
and,  just  as  in  their  case,  the  result  is  definitely 
and  conclusively  to  overturn  the  assumption.  If 
these  changes  in  the  Porto  Santo  rabbits  had  been 
due  to  the  gradual  influence  of  natural  selection 
guided  by  inscrutable  utility,  it  is  simply  impossible 
that  the  same  individual  animals,  in  the  course  of 
their  own  individual  lifetimes,  should  revert  to  the 
specific  characters  of  their  ancestral  stock  on  being 
returned  to  the  conditions  of  their  ancestral  climate. 
Therefore,  unless  any  naturalist  is  prepared  to  con- 
tradict Darwin's  statement  that  the  changes  in 
question  amount  to  changes  of  specific  magnitude, 
he  can  find  no  escape  from  the  conclusion  that 
distinctions  of  specific  importance  may  be  brought 
about  by  changes  of  habitat  alone,  without  reference 
to  utility,  and  therefore  independently  of  natural 
selection. 


Characters  as  Adaptive  and  Specific.    217 


'I 


II.  Food. 

Although,  as  yet,  little  is  definitely  known  on  the 
subject,  there  can  be  no  doubt  that  in  the  case  of 
many  animals  differences  of  food  induce  differences 
of  colour  within  the  lifetime  of  individuals,  and 
therefore  independently  of  natural  selection. 

Thus,  sundry  definite  varieties  of  the  butterfly 
Etiprepiacajacdin  be  reared  according  to  the  different 
nourishment  which  is  supplied  to  the  caterpillar ;  and 
other  butterflies  are  also  known  on  whose  colouring 
and  markings  the  food  of  the  caterpillar  has  great 
influenced 

Again,  I  may  mention  the  remarkable  case  com- 
municated to  Darwin  by  Moritz  Wagner,  of  a  species 
of  Saturnia^  some  pupae  of  which  were  transported 
from  Texas  to  Switzerland  in  T870.  The  moths 
which  emerged  in  the  following  year  were  like  the 
normal  type  in  Texas.  Their  young  were  supplied 
with  leaves  of  Jiiglans  regia,  instead  of  their  natural 
food,  y.  nigra ;  and  the  moths  into  which  these 
caterpillars  changed  were  so  different  from  their 
parents,  both  in  form  and  colour,  "that  they  were 
reckoned  by  entomologists  as  a  distinct  species  ^." 

With  regard  to  moUusks,  M.  Costa  tells  us  that 
English  oysters,  when  turned  down  in  the  Mediter- 
ranean, '■'■rapidly  became  like  the  true  Mediterranean 

'  See  especially,  Koch,  Die  Kaiipen  und  Schmetterling  der  Wet- 
teraii,  and  Die  Sch7netierUng  des  Siidwestlichen  Deiitschlands ,  whose  very 
remarkable  results  of  numerous  and  varied  experiments  are  epitomized 
by  Eimer,  Organic  Evolution,  Eng.  Trans,  pp.  147-153  ;  also  Poulton, 
Trans.  Entoti.  Sac.  1 S93. 

"^  Mivart,  On  Truth,  p.  378. 


I  I 

I 


2i8         Darwifiy  and  after  Darwin, 


'*'ri! 


'>, 


M  ,■^''1 


oyster,  altered  their  manner  of  growth,  and  formed 
promment  diverging  rays."  This  is  most  probably  due 
to  some  change  of  food.  So  likewise  may  be  the  even 
more  remarkable  case  of  Helix  nemoralis,  which  was 
introduced  from  Europe  to  Virginia  a  few  years  ago. 
Under  the  new  conditions  it  varied  to  such  an  extent 
that  up  to  last  year  no  less  than  125  varieties  had 
been  discovered.  Of  these  67,  or  more  than  half, 
are  new — that  is,  unknown  in  the  native  continent  ot 
the  species^. 

In  the  case  of  Birds,  the  Brazilian  parrot  Chrysotis 
/estiva  changes  the  green  in  its  feathers  to  red  or 
yellow,  if  fed  on  the  fat  of  certain  fishes ;  and  the 
Indian  Lori  has  its  splendid  colouring  preserved  by 
a  peculiar  kind  of  food  (Wallace).  The  Bullfinch 
is  well  known  to  *^urn  black  when  fed  on  hemp 
seeds,  and  the  Canary  to  become  red  when  fed  on 
cayenne  pepper  (Darwin).  Starting  from  these  facts, 
Dr.  Sauermann  has  recently  investigated  the  subject 
experimentally ;  and  finds  that  not  only  finches,  but 
likewise  other  birds,  such  as  fowls,  and  pigeons,  are 
subject  to  similar  variations  of  colour  when  fed  on 
cayenne  pepper ;  but  in  all  cases  the  effect  is  pro- 
duced only  if  the  pepper  is  given  to  the  young  birds 
before  their  first  moult.  Moreover,  he  finds  that 
a  moist  atmosphere  facilitates  the  change  of  colour, 
and  that  the  ruddy  hue  is  discharged  under  the 
influence  either  of  sunlight  or  of  cold.  Lastly,  he 
has  observed  that  sundry  other  materials  such  as 
glycerine  and  aniline  dyes,  produce  the  same  results  ; 
so  there  can  be  no  doubt  that  organic  compounds 
probably  occur    in    nature   which    are    capable    of 

'  Cockerell,  Nature,  vol.  xli.  p.  393. 


i 


Characters  as  Adaptive  and  Spec'f:.     219 

directly  affecting^  the  colours  of  plumage  when  eaten 
by  birds.  Therefore  the  presence  of  such  materials 
in  the  food-stuffs  of  birds  occupying  different  areas 
may  very  well  in  many  cases  determine  differences 
of  colouration,  which  are  constant  or  stable  so  long 
as  the  conditions  of  their  production  are  maintained. 


\\ 


k     i 


III.    ^rxual  Selection. 

Passing  on  now  co  causes  of  specific  change  which 
are  internal,  or  comprised  within  the  organisms 
themselves,  we  may  first  consider  the  case  of  Sexual 
Selection. 

Mr.  Wallace  rejects  the  theory  of  sexual  selection 
in  toto,  and  therefore  nothing  that  can  be  said  under 
this  head  would  be  held  by  him  to  be  relevant. 
Many  naturalists,  however,  believe  that  Darwin  was 
right  in  the  large  generalization  which  he  published 
under  this  title  ;  and  in  so  far  as  any  one  holds  that 
sexual  selection  is  a  true  cause  of  specific  modification, 
he  is  obliged  to  "L»olieve  that  innumerable  specific 
characters — especially  in  birds  and  mammals — have 
been  produced  without  reference  to  utility  (other, 
of  course,  than  utility  for  sexual  purposes),  and 
therefore  without  reference  to  natural  selection.  This 
is  so  obvious  that  I  need  not  pause  to  dilate  upon  it. 
One  remark,  however,  may  be  useful.  Mr.  Wallace 
is  able  to  make  a  much  more  effective  use  of  his 
argument  from  "  necessary  instability "  when  he 
brings  it  against  the  Darwinian  doctrine  of  sexual 
selection,  than  he  does  when  he  brings  it  against  the 
equally  Darwinian  doctrine  of  specific  characters  in 
general   not   being    all    necessarily   due    to    natural 


220         Darwin^  and  after  Darwin, 


^'ti 


selection.  In  the  latter  case,  it  will  be  remembered, 
he  is  easily  met  by  showing  that  the  causes  of  specific 
change  other  tlian  natural  selection,  such  as  food, 
climate,  &c,,  may  be  quite  as  general,  persistent,  and 
uniform,  as  natural  selection  itself;  and  therefore  in 
this  connexion  Mr.  Wallace's  argument  falls  to  the 
ground.  But  the  argument  is  much  more  formidable 
as  he  brings  it  to  bear  against  the  theory  of  sexual 
selection.  Here  he  asks,  What  is  there  to  guarantee 
the  uniformity  and  the  constancy  of  feminine  taste 
with  regard  to  small  matters  of  embellishment  through 
thousands  of  generations,  and  among  animals  living 
on  extensive  areas?  And,  as  we  have  seen  in  Part  1, 
it  is  not  easy  to  supply  an  answer.  Therefore  this 
argument  from  the  "  necessary  instability  of  charac- 
ter "  is  of  immeasurably  greater  force  as  thus  applied 
against  Darwin's  doctrine  of  sexual  selection,  than  it 
is  when  brought  against  his  doctrine  that  all  specific 
characters  need  not  necessarily  be  due  to  natural 
selection.  Therefore,  also,  if  any  one  feels  disposed 
to  attach  the  smallest  degree  of  value  to  this  argu- 
ment in  the  latter  case,  consistency  will  require  him 
to  allow  that  in  the  former  case  it  is  simply  over- 
whelming, or  in  itself  destructive  of  the  whole  theory 
of  sexual  selection.  And,  conversely,  if  his  belief  in 
the  theory  of  sexual  selection  can  survive  collision 
with  this  objection  from  instability,  he  ought  not  to 
feel  any  tremor  of  contact  when  the  objection  is 
brought  to  bear  against  his  scepticism  regarding  the 
alleged  utility  of  all  specific  characters.  For  assuredly 
no  specific  character  which  is  apparent  to  our  eyes 
can  be  supposed  to  be  so  refined  and  complex  (and 
therefore  so  presumably  inconstant  and  unstable),  as 


Chatncters  as  Adaptive  and  Specific.    221 

are  those  minute  changes  of  cerebral  structure  on 
which  a  pyschological  preference  for  all  the  refined 
shadings  and  many  pigments  of  a  complicated 
pattern  must  be  held  ultimately  to  depend.  For  this 
reason,  then,  as  well  as  for  those  previously  adduced, 
if  any  one  agrees  with  Darwin  in  holding  to  the 
theory  of  sexual  selection  notwithstanding  this  ob- 
jection from  the  necessary  instability  of  unuseful 
embellishments,  a  fortiori  he  ought  to  disregard  the 
objection  altogether  in  its  relation  to  useless  specific 
characters  of  other  kinds. 

But  quite  apart  from  this  consideration,  which 
Mr.  Wallace  and  his  followers  may  very  properly  say 
does  not  apply  to  them,  let  us  see  what  they  them- 
selves have  ma'^^Ie  of  the  facts  of  secondary  sexual 
characters — which,  of  course,  are  for  the  most  part 
specific  characters — in  relation  to  the  doctrine  of 
utility. 

Mr.  Wallace  himself,  in  his  last  work,  quotes 
approvingly  a  letter  which  he  received  in  1869  from 
the  Rev.  O  Pickard- Cambridge,  as  follows : — 


"  I  myself  doubt  that  particular  application  of  the  Darwinian 
theory  which  attributes  male  peculiarities  of  form,  structure, 
colour,  and  ornament  to  female  appetency  or  predilection. 
There  is,  it  seems  to  me,  undoubtedly  something  in  the  male 
organization  of  a  special  and  sexual  nature,  which,  of  its  own 
vital  force,  develops  the  remarkable  male  peculiarities  so 
commonly  seen,  and  of  no  imaginable  use  to  that  sex.  In  as  far 
as  these  peculiarities  show  a  great  vital  power,  they  point  out 
to  us  the  finest  and  strongest  individuals  of  the  sex,  and  show 
us  which  of  them  would  most  certainly  appropriate  to  themselves 
the  best  and  greatest  number  of  females,  and  leave  behind  them 
the  strongest  and  greatest  number  of  progeny.  And  here  would 
come  in,  as  it  appears  to  me,  the  proper  application  of  Darwin's 


222         Darwin,  and  after  Darwin. 


I.  •»■   «|ln 


-I'll 


ii!  i : 


theory  of  N;itur;il  Selection  ;  for  the  posseasors  of  greatest  vital 
ifoiver  beini^  those  most  frequently  produced  and  reproduced^  tht 
txternal  signs  of  it  would  go  on  developing  in  an  ever  increas- 
ing exaggeration^  only  to  be  checked  where  it  became  really 
detrimental  in  some  respect  or  other  to  the  individual  *.* 

Here  then  the  idea  is.  as  more  fully  expressed  by 
Mr.  Wallace  in  the  context  that  all  the  innumerable, 
frequently  considerable,  and  generally  elaborate  "  pe- 
culiarities of  form,  structure,  colour,  and  ornament," 
which  Darwin  attributed  to  sexual  selection,  are  really 
due  to  '•  the  laws  of  growth."  Diverse,  definite,  and 
constant  though  these  specific  peculiarities  be,  they 
are  all  but  the  accidental  or  adventitious  accompani- 
ments of  "vigour,"'  or  'vital  power,"  due  to  natural 
selection.  Now,  without  waiting  to  dispute  this  view, 
which  has  already  been  dealt  with  in  the  chapter 
on  Sexual  Selection  in  Part  I,  it  necessarily  follows 
that  "  a  large  proportional  number  of  specific  char- 
acters," which,  while  presenting  '*no  imaginable  use," 
are  very  much  less  remarkable,  less  considerable,  less 
elaborate,  &c.,  must  likewise  be  tiue  to  this  "correlation 
with  vital  power."  But  if  the  principle  of  correlation 
is  to  be  extended  in  this  vague  and  general  manner,  it 
appears  to  me  that  the  difference  between  Mr.  Wallace 
and  myself,  with  respect  to  the  principle  of  utility,  is 
abolished.  For  of  course  no  one  will  dispute  that 
the  prime  condition  to  the  occurrence  of  "specific 
characters,"  whether  useful  or  useless,  is  the  existence 
of  some  form  which  has  been  denominated  a  "species" 
to  present  them ;  and  this  is  merely  another  way  of 
raying  that  such  characters  cannot  arise  except  in 
correlation   with  a  general    fitness  due  to    natural 

'  Darwinism,  pp  296-7  :  italics  mine. 


characters  as  Adaptive  and  specific.    223 

selection.  Or,  to  put  the  case  in  Mr.  Wallace's 
own  words — "  This  development  [of  useless  specific 
characters]  will  necessarily  i)rocced  by  the  agency  of 
natural  selection  [as  a  necessary  condition  |  and  the 
general  laws  which  determine  the  production  of  colour 
and  of  ornamental  appendages^  The  case,  therefore, 
is  just  the  same  as  if  one  were  to  say,  for  example, 
that  all  the  ailments  of  animals  and  plants  proceed 
from  correlation  with  life  (as  a  necessary  condition), 
"and  the  general  laws  which  determine  the  production  ' 
of  ill-health,  or  of  specific  disease.  In  short,  the 
word  "  correlation  "  is  here  used  in  a  totally  different 
sense  from  that  in  which  it  is  used  by  Darwin,  and  in 
which  it  .3  elsewhere  used  by  Wallace  for  the  purpose 
of  sustaining  his  doctrine  of  specific  characters  as 
necessarily  useful.  To  say  that  a  useless  character 
A  is  correlated  with  a  useful  one  13,  is  a  very  different 
thing  from  saying  that  A  is  *'  correlated  with  vital 
power,"  or  with  the  general  conditions  to  the  exist- 
ence of  the  species  to  which  it  belongs.  So  far  as  the 
present  discussion  is  concerned,  no  exception  need  be 
taken  to  the  latter  statement.  For  it  simply  sur- 
renders the  doctrine  against  which  I  am  contending. 


IV.    Isolation. 

It  is  the  opinion  of  many  naturalists  who  are 
well  entitled  to  have  an  opinion  upon  the  subject 
that,  in  the  words  of  Mr.  Dixon,  '  Isolation  can 
preserve  a  non-beneficial  as  effectually  as  natural 
selection  can  preserve  a  beneficial  variation  ^"  The 
ground  on  which  this  doctrine  rests  is  thus  clearly 

'  Naiurt,  Toi.  xxxiri.  p.  loa 


¥'V:i 


224         Darwin y  and  after  Darwin. 


I  If  ',.-  .i  . 


IK,;,-!' 

•'t.,    '-I'., 

'Nil; 


fi  'A 


m% 


set  forth  by  Mr.  Gulick : — "  The  fundamental  cause 
of  this  seems  to  lie  in  the  fact  that  no  two  portions  of 
a  species  possess  exactly  the  same  average  characters  ; 
and,  therefore,  that  the  initial  differences  are  for 
ever  reacting  on  the  environment  and  on  each  other 
in  such  a  way  as  to  ensure  increasing  divergence 
in  each  generation,  as  long  as  the  individuals  of 
the  two  groups  are  kept  from  intergenerating^."  In 
other  words,  as  soon  as  a  portion  of  a  species  is 
separated  from  the  rest  of  that  species,  so  that 
breeding  between  the  two  portions  is  no  longer 
possible,  the  general  average  of  character:  in  the 
separated  portion  not  being  in  all  respects  precisely 
the  same  as  it  is  in  the  other  portion,  the  result  of 
in-breeding  among  all  individuals  of  the  separated 
portion  will  eventually  be  different  from  that  which 
obtains  in  the  other  portion ;  so  that,  after  a  number 
of  generations,  the  separated  portion  may  become 
a  distinct  species  from  the  effect  of  isolation  alone. 
Even  without  the  aid  of  isolation,  any  original  dif- 
ference of  average  characters  miay  become,  as  it 
were,  magnified  in  successive  generations,  provided 
that  the  divergence  is  not  harmful  to  the  individuals 
presenting  it.,  and  that  it  occurs  in  a  sufficient  pro- 
portional number  of  individuals  not  to  be  immedi- 
ately swamped  by  intercrossing.  For,  as  Mr.  Murphy 
has  pointed  out,  in  accordance  with  Delboeuf's  law, 
"if,  in  any  species,  a  number  of  individuals,  bearing 
a  ratio  not  infinitely  small  to  the  entire  number  of 
births,  are  in  every  generation  born  with  a  particular 
variation   which   is   neither   beneficial   nor  injurious, 

*  Divergent  Kvoluio*i  through  Cumuiaiivt  Segregation,  Linn.  Joum. 
Zoology,  vol.  XX.  p.  215. 


8    Ji 

hi 


Characters  as  Adaptive  and  Specific.    225 

and  if  it  be  not  counteracted  by  reversion,  then 
the  proportion  of  the  new  variety  to  the  original 
form  will  increase  till  it  appvoaches  indefinitely 
near  to  equality^."  Now  even  Mr.  Wallace  himself 
allows  that  this  must  be  the  case  ;  and  thinks  that  in 
these  considerations  we  may  find  an  explanation  of 
the  existence  of  certain  definite  varieties,  such  as 
the  melanic  form  of  the  jaguar,  the  brindled  or  ring- 
eyed  guillemot,  &c.  But,  on  the  other  hand,  he 
thinks  that  such  varieties  must  always  be  unstable, 
and  continually  produced  in  varying  proportions 
from  the  parent  forms.  We  need  not,  however, 
wait  to  dispute  this  arbitrary  assumption,  because 
we  can  see  that  it  fails,  even  as  an  assumption,  in 
all  cases  where  the  superadded  influence  of  isolation 
is  concerned.  Here  there  is  nothing  to  intercept 
the  original  tendency  to  divergent  evolution,  which 
arises  directly  out  of  the  initially  different  average 
of  qualities  presented  by  the  isolated  section  of  the 
species,  as  compared  with  the  rest  of  that  species  *. 


m 


*  Habit  and  Intelligence,  p.  341. 

"  Allusion  may  here  again  be  made  to  the  *.tise  of  the  niata  cattle. 
For  here  is  a  case  where  a  very  extreme  variety  is  certainly  not  unstable, 
nor  produced  in  vjtrymg  proportions  from  the  parent  form.  Moreover, 
as  we  have  seen  in  the  precedin^^;  chapter,  this  almost  monstrous 
variety  most  probably  originated  as  an  individual  sport—  being  after- 
wards maintained  and  multiplied  for  a  time  by  artificial  selection.  Now, 
whether  or  not  this  was  the  case,  we  can  very  well  see  that  it  may  have 
been.  Hence  it  will  serve  to  illustrate  another  possibility  touching  the 
origin  and  maintenance  of  useless  specific  characters.  For  what  is 
to  prevent  an  individual  congenital  variation  of  any  kind  (provided  it 
be  not  harmful)  from  perpetuating  itself  as  a  "  varietal,"  and  eventually, 
should  offspring  become  sufficiently  numerous,  a  "  specific  character  "  ? 
There  is  nothing  to  prevent  this,  save  panmixia,  or  the  presence  of  free 
intercrossing.  But,  as  we  shall  see  in  the  next  division  of  this  treatise, 
there  are  in  nature  many  forms  of  isolation.  Hence,  as  often  as  a  small 
number  of  individuals  may  have  experienced  isolation  in  any  of  its  forms, 

IL  Q 


: 


si! 


t"N 


'S  I'll 


iilll^ 


iMr: 


226        Darwin,  and  after  Darwin. 

As  we  shall  have  to  consider  the  important  principle 
of  isolation  more  fully  on  a  subsequent  occasion, 
I  need  not  deal  with  it  in  the  present  connexion, 
further  than  to  remark  that  in  this  principle  we  have 
what  appears  to  me  a  full  and  adequate  condition  to 
the  rise  and  continuance  of  specific  characters  which 
need  not  necessarily  be  adaptive  characters.  And,  when 
we  come  to  consider  the  facts  of  isolation  more  closely, 
we  shall  find  superabundant  evidence  of  this  having 
actually  been  the  case. 

V.    Laws  of  Growth. 

Under  this  general  term  Darwin  included  the  opera- 
tion of  all  unknown  causes  internal  to  organisms 
leading  to  modifications  of  form  or  structure — such 
modifications,  therefore,  appearing  to  arise,  as  he 
says  "  spontaneously,"  or  without  reference  to  utility. 
That  he  attributed  no  small  importance  to  the  opera- 
opportunity  for  perpetuation  will  have  been  given  to  any  congenital 
variations  wlii  :h  may  happen  to  arise.  Should  any  of  these  be  pronounced 
variations,  it  would  afterwards  be  ranked  as  a  specific  character. 
I  do  not  myself  think  that  this  is  the  way  in  which  indifferent  specific 
characters  usually  originate.  On  the  contrary,  I  believe  that  their 
origin  is  most  frequently  due  to  the  influence  of  isolation  on  the  average 
characters  of  the  whole  population,  as  briefly  stated  in  the  text.  But 
here  it  seems  worth  while  to  uotice  this  possibility  of  their  occa- 
sionally arising  as  merely  individual  variations,  afterwards  perpetuated 
by  any  of  the  numerous  isolating  conditions  which  occur  in  nature. 
For,  if  this  can  be  the  case  with  a  varietal  form  so  extreme  as  to  border 
on  the  monstrous,  much  more  can  it  be  so  with  such  minute  differences 
as  frequently  go  to  constitute  specific  distinctions  It  is  the  business  of 
species-makers  to  search  out  such  distinctions,  no  matter  how  trivial, 
and  to  record  them  as  "  specific  characters."  Consequently,  wherever 
in  nature  a  congenital  variation  happens  to  arise,  and  to  be  perpetuated 
by  the  force  of  heredity  alone  under  any  of  the  numeroas  forms  of  isola- 
tion which  occur  in  nature,  there  will  be  a  case  analogous  to  that  of  the 
niata  cattle. 


Characters  as  Adaptive  and  Specific.    227 

tion  of  these  principles  is  evident  from  the  last 
edition  of  the  Origin  of  Species.  But  as  these  "  laws 
of  growth "  refer  to  causes  confessedly  unknown, 
I  will  not  occupy  space  by  discussing  this  division 
of  our  subject — further  than  to  observe  that,  as  we 
shall  subsequently  see,  many  of  the  facts  which 
fall  under  it  are  so  irreconcilably  adverse  to  the 
Wallacean  doctrine  of  specific  characters  as  univer- 
sally adaptive,  that  in  the  face  of  them  Mr.  Wallace 
himself  appears  at  times  to  abandon  his  doctrine 
in  toto. 


^    1 


Q  » 


!t-^.;:;;;^ 


mwi 


m 


CHAPTER  IX. 

Characters  as  Adaptive  and  Specific 

(continued). 

It  must  have  appeared  strange  that  hitherto  I 
should  have  failed  to  distinguish  between  "true 
species"  and  merely  "climatic  varieties."  But  it 
will  conduce  to  clearness  of  discussion  if  we  con- 
sider our  subject  point  by  point.  Therefore,  having 
now  given  a  fair  statement  of  the  facts  of  climatic 
variation,  I  propose  to  deal  with  their  theoretical 
implications — especially  as  regards  the  distinction 
which  naturalists  are  in  the  habit  of  drawing 
between  them  and  so-called  true  species. 

First  of  all,  then,  what  is  this  distinction  ?  Take, 
for  example,  the  case  of  the  Porto  Santo  rabbits. 
To  almost  every  naturalist  who  reads  what  has  been 
said  touching  these  animals,  it  will  have  appeared 
that  the  connexion  in  which  they  are  adduced  is 
wholly  irrelevant  to  the  question  in  debate.  For, 
it  will  be  said  that  the  very  fact  of  the  seemingly 
specific  differentiation  of  these  animals  having  proved 
to  be  illusory  when  some  of  them  were  restored  to 
their  ancestral  conditions,  is  proof  that  their  peculiar 
characters  are  not  specific  characters  ;  but  only  what 
Mr.  Wallace  would  term  "  individual   characters,"  or 


li:  I 


I  '  i     I 


Characters  as  Adaptive  and  Specific,    ^sx^ 

variations  that  are  not  inherited.  And  the  same 
remark  applies  to  all  the  other  cases  which  have  been 
adduced  to  show  the  generality  and  extent  of  climatic 
variation,  both  in  other  animals  and  also  in  plants. 
Why,  then,  it  will  be  asked,  commit  the  absurdity  of 
adducing  such  cases  in  the  present  discussion  ?  Is  it 
not  self-evident  that  however  general,  or  however 
considerable,  such  merely  individual,  or  non-heritable, 
variations  may  be,  they  cannot  possibly  have  ever  had 
anything  to  do  with  the  origin  of  species  ?  Therefore,  i-. 
it  not  simply  preposterous  to  so  much  as  mention 
them  in  relation  to  the  question  touching  the  utility 
of  specific  characters? 

Well,  whether  or  not  it  is  absurd  and  preposterous 
to  consider  climatic  variations  in  connexion  with  the 
origin  of  species,  will  depend,  and  depend  exclusively, 
on  what  it  is  that  we  are  to  understand  by  a  species. 
Hitherto  I  have  assumed,  for  the  sake  of  argument, 
that  we  all  know  what  is  meant  by  a  species.  But 
the  time  has  now  come  for  showing  that  such  is  far 
from  being  the  case.  And  as  it  would  be  clearly 
absurd  and  preposterous  to  conclude  anything  with 
regard  to  specific  characters  before  agreeing  upon 
what  we  mean  by  a  character  as  specific,  I  will 
begin  by  giving  all  the  logically  possible  definitions 
of  a  species. 

1 .  A  group  of  individuals  descended  by  way  of  natural 
generation  from  an  originally  and  specially  created  type. 

This  definition  may  be  taken  as  virtually  obsolete. 

2.  A  group  of  i^idividuals  which^  while  fully  fertile 
inter  se,  are  sterile  with  all  other  individuals — or^  at 
a7iy  rate,  do  not  generate  fidly  fertile  hybrids. 

This  purely  physiological  definition  is  not  nowadays 


'I- 
j 


iU 


i 


••^'!»l' 


\     ■iM 


M   !i 


r\ 


)  i 


230        Darwin,  and  after  Darwin, 

entertained  bv  any  naturalist.  Even  though  the 
physiological  distinction  be  allowed  to  count  for 
something  in  otherwise  doubtful  cases,  no  systematist 
would  constitute  a  species  on  such  grounds  alone. 
Therefore  we  need  not  concern  ourselves  with  this 
definition,  further  than  to  observe  that  it  is  often 
taken  as  more  or  less  supplementary  to  each  of  the 
following  definitions. 

3.  A  group  of  mdividuals  which,  hozvever  many 
characters  they  share  ivith  other  individuals,  agree  in 
presenting  one  or  more  characters  of  a  pecidiar  kind, 
with  some  certain  degree  of  distinctness. 

In  this  we  have  the  definition  which  is  practically 
followed  by  all  naturalists  at  the  present  time.  But, 
as  we  shall  presently  see  more  fully,  it  is  an  extremely 
lax  definition.  For  it  is  impossible  to  determine,  by 
any  fixed  and  general  rule,  what  degree  of  distinctness 
on  the  part  of  peculiar  characters  is  to  be  taken  as 
a  uniform  standard  of  specific  separation.  So  long 
as  naturalists  believed  in  special  creation,  they  could 
feel  that  by  following  this  definition  (3)  they  were 
at  any  rate  doing  their  best  to  tabulate  very  real 
distinctions  in  nature — ^viz.  between  types  as  originally 
produced  by  a  supernatural  cause,  and  as  subsequently 
more  or  less  modified  (i.  e.  within  the  limits  imposed 
by  the  test  of  cross-fertility)  by  natural  causes.  But 
evolutionists  are  unable  to  hold  any  belief  in  such 
real  distinctions,  being  confessedly  aware  that  all 
distinctions  between  species  and  varieties  are  purely 
artificial.  So  to  speak,  they  well  know  that  it  is 
they  themselves  who  create  species,  by  determining 
round  wi.at  degrees  of  differentiation  their  diagnostic 
boundaries  shall  be  drawn.    And,  seeing  that  these 


Characters  as  Adaptive  anc^  Specific.    231 

degrees  of  differentiation  so  frequently  shade  into 
one  another  by  indistinguishable  stages  (or,  rather, 
that  they  always  do  so,  unless  intermediate  varieties 
have  perished),  modern  naturalists  are  well  awake  to 
the  impossibility  of  securing  any  approach  to  a  uniform 
standard  of  specific  distinction.  On  this  account 
many  of  them  feel  a  pressing  need  for  some  firmer 
definition  of  a  species  than  this  one — which,  in 
point  of  fact,  scarcely  deserves  to  be  regarded  as 
a  definition  at  all,  seeing  that  it  does  not  formu- 
late any  definite  criterion  of  specific  distinctness, 
but  leaves  every  man  to  follow  his  own  standards 
of  discrimination.  Now,  as  far  as  I  can  see, 
there  are  only  two  definitions  of  a  species  which 
will  yield  to  evolutionists  the  steady  and  uniform 
criterion  required.  These  two  definitions  are  as 
follows. 

4.  A  group  of  individuals  which,  hotvever  many 
characters  they  share  ivith  other  individuals,  agree  in 
presenting  one  or  more  characters  of  a  peculiar  and 
hereditary  kind,  with  so7ne  certain  degree  of  dis- 
tinctness. 

It  will  be  observed  that  this  definition  is  exactly 
the  same  as  the  last  one,  save  in  the  addition  of  the 
words  "and  hereditary."  But,  it  is  needless  to  say, 
the  addition  of  these  words  is  of  the  highest  im- 
portance, inasmuch  as  it  supplies  exactly  that  objective 
and  rigid  criterion  of  specific  distinctness  which  the 
preceding  definition  lacks.  It  immediately  gets  rid 
of  the  otherwise  hopeless  wrangling  over  species  as 
"good"  and  "bad,"  or  "true"  and  "climatic,"  of 
which  (as  we  have  seen)  Kerner's  essay  is  such 
a  remarkable  outcome.     Therefore  evolutionists  have 


iii^ 


If 


*5 


•I 

111 


ml 

liii  *  i 


It  I 


232        Darwm,  and  after  Darwin. 

more  and  more  grown  to  lay  stress  on  the  hereditary 
character  of  such  pecuh'arities  as  they  select  for 
diagnostic  features  of  specific  distinc!:ncss.  Indeed 
it  is  not  too  much  to  say  that,  at  the  present  time, 
evolutionists  in  general  recognize  this  character  as, 
theoretically,  indispensable  to  the  constitution  of 
a  species.  But  it  is  likewise  not  too  much  to  say 
that,  practically,  no  one  of  our  systematic  naturalists 
has  hitherto  concerned  himself  with  this  matter. 
At  all  events,  I  do  not  know  of  any  who  has  ever 
taken  the  trouble  to  ascertain  by  experiment,  with 
regard  to  any  of  the  species  which  he  has  consti- 
tuted, whether  the  peculiar  characters  on  which  his 
diagnoses  have  been  founded  are,  or  are  not,  heredi- 
tary. Doubtless  the  labour  of  constituting  (or,  still 
more,  of  ^^-constituting)  species  on  such  a  basis  of 
experimental  inquiry  would  be  insuperable ;  while, 
even  if  it  could  be  accomplished,  would  prove  unde- 
sirable, on  account  of  the  chaos  it  would  produce 
in  our  specific  nomenclature.  But,  all  the  same,  we 
must  remember  that  this  nomenclature  as  we  now 
have  it — and,  therefore,  the  partitioning  of  species  as 
we  have  now  made  them — has  no  reference  to  the 
criterion  of  heredity.  Our  system  of  distinguishing 
between  sp'^cies  and  varieties  is  not  based  upon  the 
definition  which  we  are  now  considering,  but  upon 
that  which  we  last  considered — frequently  coupled, 
to  some  undefinable  extent,  with  No.  2. 

5.  There  is,  however,  yet  another  and  closer  defini- 
tion, which  may  be  suggested  by  the  ultra- Darwinian 
school,  who  maintain  the  doctrine  of  natural  selection 
as  the  only  possible  cause  of  the  origin  of  species, 
namely : — 


I 


Characters  as  Adaptive  and  Specific.    233 

A  group  of  individuals  which  ^  however  many 
characters  they  share  with  other  individjtals,  agree 
in  presenting  one  or  more  characters  of  a  peculiar, 
hereditary,  and  adaptive  kind,  with  some  certain  degree 
of  distinctness. 

Of  course  this  definition  rests  upon  the  dogma  of 
utility  as  a  necessary  attribute  of  characters  qud 
specific — i.  e.  the  dogma  against  which  the  whole 
of  the  present  discussion  is  directed.  Therefore 
all  I  need  say  with  reference  to  it  is,  that  at 
any  rate  it  cannot  be  adduced  in  any  argun  ,nt 
where  the  validity  of  its  basal  dogma  is  in  question. 
For  it  would  be  a  mere  begging  of  this  question  to 
argue  that  every  species  must  present  at  least  one 
peculiar  and  adaptive  character,  because,  according 
to  definition,  unless  an  organic  type  does  present  at 
least  one  such  character,  it  is  not  a  specific  type. 
Moreover,  and  quite  apart  from  this,  it  is  to  be  hoped 
that  naturalists  as  a  body  will  never  consent  to  base 
their  diagnostic  work  on  what  at  best  must  always 
be  a  highly  speculative  extension  of  the  Darwinian 
theory.  While,  lastly,  if  they  were  to  do  so  with 
any  sort  of  consistency,  the  precise  adaptation  which 
each  peculiar  character  subserves,  and  which  because 
of  this  adaptation  is  constituted  a  character  of  specific 
distinction,  would  have  to  be  determined  by  actual 
observation.  For  no  criterion  of  specific  distinction 
could  be  more  vague  and  mischievous  than  this  one, 
if  it  were  to  be  applied  on  grounds  of  mere  inference 
that  such  and  such  a  character,  because  seemingly 
constant,  must  "necessarily"  be  either  useful,  vestigial, 
or  correlated. 

Such    then,   as    far    as    I    can    see,    are  all    the 


i;    il 


Hi 


234         Darwin,  and  after  Darwin, 


'^< 


\\ 


't 


•^.   ,  '111 


II 


ii 


definitions  of  a  species  that  are  logically  possible^ 
Which  of  them  if.  chosen  by  those  who  maintain 
the  necessary  usefulness  of  all  specific  characters  ? 
Observe,  it  is  for  those  who  maintain  this  doctrine 
to  choose  thei''  definition :  it  is  not  for  me  to  do  so. 
My  contention  is,  that  the  term  does  not  admit  of 
any  definition  sufficiently  close  and  constant  to  serve 
as  a  basis  for  the  doctrine  in  question — and  this  for 
the  simple  reason  that  species-makers  have  never 
agreed  among  themselves  upon  any  criterion  of  specific 
distinction.  My  opponents,  on  the  other  hand,  are 
clearly  bound  to  take  an  opposite  view,  because, 
unless  they  suppose  that  there  is  some  such  definition 
of  a  species,  they  would  be  self-convicted  of  the 
absurdity  of  maintaining  a  great  generalization  on 
a  confessedly  untenable  basis.  For  example,  a  few 
years  ago  I  was  allowed  to  raise  a  debr^  in  the 
Biological  Section  of  the  British  Association  on  the 
question  to  which  the  present  chapters  are  devoted. 
But  the  debate  ended  as  I  had  anticipated  that  it 
must  end.  No  one  of  the  naturalists  present  could 
give  even  the  vaguest  definition  of  what  was  meant  by 

^  It  is  almost  needless  to  say  that  by  a  definition  as  "  logical " 
is  meant  one  which,  while  including  all  the  differentiae  of  the  thing 
delined,  exclirles  any  qualities  wliich  that  thing  may  share  in  common 
with  any  other  thing.  But  by  definitions  as  "logically  possible "  I  mean 
the  number  of  separate  definitions  which  admit  of  being  correctly  given 
of  the  same  thing  from  different  points  of  view.  Thus,  for  instance,  in 
the  present  case,  since  the  above  has  been  in  type  the  late  M.  Quatre- 
fages'  posthumous  work  on  Darwin  et  ses  Prkurseurs  Franfais  has 
been  published,  and  gives  a  long  list  of  definitions  of  the  term  "species" 
which  from  time  to  time  have  been  enunciated  by  as  many  naturalists 
of  the  highest  standing  as  such  (pp.  1S6-187).  But  while  none  of 
these  twenty  or  more  definitions  is  logical  in  the  sense  just  defined, 
they  all  present  one  or  other  of  the  diffeicnliae  given  by  those  in 
the  text. 


m: 


Characters  as  Adaptive  and  Specific.     235 


a  species-  -or,  consequently,  of  a  character  as  specific. 
On  this  account  the  debate  eiuled  in  as  complete 
a  destruction  as  was  possible  of  the  doctrine  that 
all  the  distinctive  characters  of  every  species  must 
necessarily  be  useful,  vestigial,  or  correlated.  For  it 
became  unquestionable  that  the  same  generalization 
admitted  of  being  made,  with  the  same  degree  of 
effect,  touching  all  the  distinctive  characters  of  every 
"snark." 

Probably,  however,  it  will  be  thought  unfair  to  have 
thus  sprung  a  difficult  question  of  definition  in  oral 
debate.  Therefore  I  allude  to  this  fiasco  at  the 
British  Association,  merely  for  the  purpose  of  em- 
phasizing the  necessity  of  agreeing  upon  some  defini- 
tion of  a  species,  before  we  can  conclude  anything  with 
regard  to  the  generalization  of  specific  characters  as 
necessarily  due  to  natural  selection.  But  when  a 
naturalist  has  had  full  time  to  consider  this  funda- 
mental matter  of  definition,  and  to  decide  on  what 
his  own  shall  be,  he  cannot  complain  of  unfairness  on 
the  part  of  any  one  else  who  holds  him  to  what  he 
thus  says  he  means  by  a  species.  Now  Mr.  Wallace, 
in  his  last  work,  has  given  a  matured  statement  of 
what  it  is  that  he  means  by  a  species.  This,  there- 
fore, I  will  take  as  the  avowed  basis  of  his  doctrine 
touching  the  necessary  origin  and  maintenance  of  all 
specific  characters  by  natural  selection.  His  definition 
is  as  follows : — 


i 


"  An  assemblacje  of  individuals  which  have  become  somewhat 
moditied  in  structure,  form,  and  constitution,  so  as  to  adapt  them 
to  slightly  diff:rent  conditions  of  life ;  which  can  be  differen- 
tiated from  allied  2  .semblages;  which  reproduce  their  like  ;  which 
usually  breed  together ;  and,  perhaps,  when  crossed  with  their 


hm 


%  3t 


S' 


u,,    ■■('I 

If*'' 


m 


i 


236         Darwin f  and  after  Darwin. 

near  allies,  always  produce  offspring  which  arc  more  or  less  sterile 
infer  jtf '." 

From  this  definition  the  portion  which  I  have 
italicized  must  be  omitted  in  the  present  discussion, 
for  the  reasons  already  given  while  considering 
definition  No.  .5.  What  remains  is  a  combination  of 
Nos.  2  and  4.  According  to  Mr.  Wallace,  therefore, 
(lur  criterion  of  a  species  is  to  be  the  heredity  of 
peculiar  characters,  combined,  perhaps,  with  a  more 
or  less  exclusive  fertility  of  the  component  individuals 
inter  se.  This  is  the  basis  on  which  his  generalization 
of  the  utility  of  specific  characters  as  necessary  and 
universal  is  reared.  Here,  then,  we  have  something 
definite  to  go  upoh,  at  all  events  as  far  as  Mr.  Wallace 
is  concerned.  Let  us  see  how  far  such  a  basis  of 
definition  is  competent  to  sustain  his  generalization. 

First  of  all  it  must  be  remarked  that,  as  species 
have  actually  been  constituted  by  systematists,  the 
test  of  exclusive  fertility  does  not  apply.  For  my 
own  part  I  think  this  is  to  be  regretted,  because 
I  believe  that  such  is  the  only  natural — and  there- 
fore the  only  firm — basis  on  which  specific  dis- 
tinctions can  be  reared.  But,  as  previously  observed, 
this  is  not  the  view  which  has  been  taken  by  our 
species-makers.  At  most  they  regard  the  physio- 
logical criterion  as  but  lending  some  additional  weight 
to  their  judgement  upon  morphological  features,  in 
cases  where  it  is  doubtful  whether  the  latter  alone 
are  of  sufificient  distinctness  to  justify  a  recognition 
of  specific  value.  Or,  conversely,  if  the  morphological 
features  are  clearly  sufficient  to  justify  such  a  recog- 
nition, yet  if  it  happens   to  be  known  that  there  is 

'  Darwinism,  p.  167. 


m 


Characters  as  Adaptive  and  Specific.    237 

full  fertility  between  the  form  presenting  them  and 
other  forms  which  do  not,  then  the  latter  fact  will 
usually  prevent  naturalists  from  constituting^  the  well 
differentiated  form  a  species  on  grounds  of  its  morpho- 
logical features  alone — as,  for  instance,  in  the  case  of 
our  domesticated  varieties.  In  short,  the  physiological 
criterion  has  not  been  employed  with  sufficient  close- 
ness to  admit  of  its  being  now  comprised  within  any 
practical  definition  of  the  term  *■  species  " — if  by  this 
term  we  are  to  understand,  not  what  any  one  may 
think  species  ought  to  be^  but  what  species  actually 
are,  as  they  have  been  constituted  for  us  by  their 
makers. 

From  all  this  it  follows  that  the  definition  of  the 
term  "species"  on  which  Mr.  Wallace  relies  for  his 
deduction  with  respect  to  specific  characters,  is  the 
definition  No.  4.  In  other  words,  omitting  his  petitio 
principii  and  his  allusion  to  the  test  of  fertility,  the 
great  criterion  in  his  view  is  the  criterion  of  Kcrc  Iky. 
And  in  this  all  other  evolutionists,  of  whatever  school, 
will  doubtless  agree  with  him.  They  will  recognize 
that  it  is  really  the  distinguishing  test  between 
"  climatic  varieties  "  and  "  true  species,"  so  that  how- 
ever widely  or  however  constantly  the  former  may 
diverge  from  one  another  in  regard  to  their  peculiar 
characters,  they  are  not  to  be  classed  among  the 
latter  unless  their  peculiar  characters  are  likewise 
hereditary  characters. 

Now,  if  we  are  all  agreed  so  far,  the  only  question 
that  remains  is  whether  or  not  this  criterion  of 
Heredity  is  capable  of  supplying  a  basis  for  the 
generalization,  that  all  characters  which  have  been 
ranked    as    of    specific    value    must    necessarily    be 


:*■ 


'     "-"I'M 


I 


ii' 


■  I 

If] 


238         Darwin,  and  after  Darwin. 

regarded  as  presenting  also  an  adaptive,  or  life- 
serving,  value?  I  will  now  endeavour  to  show  that 
there  are  certain  very  good  reasons  for  answering 
this  question  in  the  negative. 

(A.) 

In  the  first  place,  even  if  the  modifications  induced 
by  the  direct  action  of  a  changed  environment  are 
not  hereditary,  who  is  to  know  that  they  are  not? 
Assuredly  not  the  botanist  or  zoologist  who  in 
a  particular  area  finds  what  he  is  fully  entitled  to 
regard  as  a  well-marked  specific  type.  Only  by 
experiments  in  transposition  could  it  be  proved 
that  the  modifications  have  been  produced  by  local 
conditions ;  and  although  the  researches  of  many 
experimentalists  have  shown  how  considerable  and 
how  constant  such  modifications  may  be,  where  is  the 
systematic  botanist  who  would  ever  think  of  trans- 
planting an  apparently  new  species  from  one  distant 
area  to  another  before  he  concludes  that  it  is  a  new 
species?  Or  where  is  the  systematic  zoologist  who 
would  take  the  trouble  to  transport  what  appears 
to  be  an  obviously  endemic  species  of  animal  from 
one  country  to  another  before  venturing  to  give  it 
a  new  specific  name?  No  doubt,  both  in  the  case 
of  plants  and  animals,  it  is  tacitly  assumed  that 
constant  differences,  if  sufficient  in  amount  to  be  re- 
garded as  specific  differences  are  hereditary  ;  but  there 
is  not  one  case  in  a  hundred  where  the  validity  of  this 
assumption  has  ever  been  tested  by  experiments 
in  transposition.  Therefore  naturalists  are  apt  to 
regard  it  as  remarkable  when  the  few  experiments 
which  have   been  made  in  this  direction  are  found 


m 


Characters  as  Adaptive  and  Specific.    239 

to  negative  their  assumption — for  example,  that 
a  diagnostic  character  in  species  of  the  genus  Hiera- 
tium  is  found  by  transplantation  not  to  be  hereditary, 
or  that  the  several  named  species  of  British  trout 
are  similarly  proved  to  be  all  '  local  varieties ''  of  one 
another.  But,  in  point  of  fact,  there  ought  to  be 
nothing  to  surprise  us  in  such  results — unless,  indeed, 
it  is  the  unwarrantable  nature  of  the  assumption  that 
any  given  differences  of  size,  form,  colour,  &c.,  which 
nat'iralists  may  have  regarded  as  of  specific  value, 
are,  on  this  account,  hereditary.  Indeed,  so  sur- 
prising is  this  assumption  in  the  face  of  what  we 
know  touching  both  the  extent  and  the  constancy 
of  climatic  variation,  that  it  seems  to  me  such  a 
naturalist  as  Kerner,  who  never  considers  the 
criterion  of  heredity  at  all,  is  less  assailable  than  those 
who  profess  to  constitute  this  their  chief  criterion 
of  specific  distinction.  For  it  is  certain  that  whatever 
their  professions  may  have  nowadays  become,  sys- 
tematic naturalists  have  never  been  in  the  habit 
of  really  following  this  criterion.  In  theory  they  have 
of  late  years  attached  more  and  more  weight  to 
definition  No.  4 ;  but  in  practice  they  have  always 
adopted  definition  No.  3.  The  consequence  is,  that 
in  literally  numberless  cases  (particularly  in  the 
vegetable  kingdom)  "specific  characters"  are  assumed 
to  be  hereditary  characters  merely  because  systematic 
naturalists  have  bestowed  a  specific  name  on  the 
form  which  presents  them.  Nor  is  this  all.  For, 
conversely,  even  when  it  is  known  that  constant  mor- 
phological characters  are  unquestionably  hereditary 
characters,  if  they  happen  to  present  but  small 
degrees  of  divergence  from  those  of  allied  forms,  then 


.   II 


W'l:  I 


'  -Nil 


t., 


*, 


•tin. 
\ 


240         Darwin,  and  after  Darwin. 

the  form  which  presents  them  is  not  ranked  as  a 
species,  but  as  a  constant  variety.  In  other  words, 
when  definitions  3  and  4  are  found  to  clash,  it  is  not 
4,  but  3,  that  is  followed.  In  short,  even  up  to  the 
present  time,  systematic  naturalists  play  fast  and 
loose  with  the  criterion  of  Heredity  to  such  an 
extent,  that,  as  above  observed,  it  has  been  rendered 
well  nigh  worthless  in  fact,  whatever  may  be  thought 
of  it  in  theory. 

Now,  unless  all  this  can  be  denied,  what  is  the 
use  of  representing  that  a  species  is  distinguished 
from  a  variety — "climatic"  or  otherwise — by  the 
fact  that  its  constituent  individuals  *'  reproduce  their 
like"?  We  are  not  here  engaged  on  any  abstract 
question  of  what  might  have  been  the  best  principles 
of  specific  distinction  for  naturalists  to  have  adopted. 
We  are  engaged  on  the  practical  question  of  the 
principles  which  they  actually  have  adopted.  And 
of  these  principles  the  reproduction  of  like  by  like, 
under  all  circumstances  of  environment,  has  been 
virtually  ignored. 

(B.) 

In  the  second  place,  supposing  that  the  criterion 
of  Heredity  had  been  as  universally  and  as  rigidly 
employed  by  our  systematists  in  their  work  of  con- 
structing species  as  it  has  been  but  occasionally  and 
loosely  employed,  could  it  be  said  that  even  then  a  basis 
would  have  been  furnished  for  the  doctrine  that  all  spe- 
cific characters  must  necessarily  be  useful  characters? 
Obviously  not,  and  for  the  following  reasons. 

It  is  admitted  that  climatic  characters  are  not 
necessarily — or    even    generally — useful    characters. 


n 


1 

% 

J 


I 


CharacU  ••9  as  Adaptive  and  Specific.    241 

Consequently,  if  there  be  any  reason  for  believing 
that  climatic  characters  may  become  in  time  here- 
ditary characters,  the  doctrine  in  question  would 
co'Uapse,  even  supposing  that  all  specific  types  were 
to  be  re-constituted  on  a  basis  of  experim.ental 
inquiry,  for  the  purpose  of  ascertaining  which  of 
them  conform  to  the  test  of  Heredity.  Now  there 
are  very  good  reasons  for  believing  that  climatic 
characters  not  unfrequently  do  become  hereditary 
characters ;  and  it  was  mainly  in  view  of  those 
reasons  that  I  deemed  it  worth  while  to  devote  so 
much  space  in  the  preceding  chapter  to  the  facts  of 
climatic  variation.  I  will  now  state  the  reasons  in 
question  under  two  different  lines  of  argument. 

We  are  not  as  yet  entitled  to  conclude  definitely 
against  the  possible  inheritance  of  acquired  char- 
acters. Consequently,  we  are  not  as  yet  entitled 
to  assume  that  climatic  characters — i.  e.  characters 
acquired  by  converse  with  a  new  environment,  con- 
tinued, say,  since  the  last  glacial  period — can  never 
have  become  congtnital  characters.  But,  if  they  ever 
have  become  cong^».'nital  characters,  they  will  have 
become,  at  all  events  as  a  general  rule,  congenital 
characters  that  are  useless ;  for  it  is  conceded  that, 
qtid  climatic  characters,  they  have  not  been  due  to 
natural  selection. 

Doubtless  the  followers  of  Weismann  will  repudiate 
this  line  of  argument,  if  not  as  entirely  worthless, 
at  all  events  as  too  questionable  to  be  of  much 
practical  worth.  But  even  to  the  followers  of  Weis- 
mann it  may  be  pointed  out,  that  the  Wallacean 
doctrine  of  the  origin  of  all  specific  characters  by 
means  of  natural  selection  was  propounded  many  years 

II.  R 


i 

1    i 

i! 


Im 


VI 


•»* 


'^V      111 


rim 


iu    'h 


'hi 


Jl  I 


242         Darwin,  and  after  Darwin. 

before  either  Galton  or  Weismann  had  questioned 
the  transmission  of  acquii.-'i  characters.  However. 
I  allow  that  this  line  of  argument  has  now  become 
— for  the  time  being  at  all  events — a  dubious  line,  and 
will  therefore  at  once  pass  on  to  the  second  line, 
which  is  not  open  to  doubt  from  any  quarter. 

Whether  or  not  we  accept  Weismann's  views,  it 
will  here  be  convenient  to  employ  his  terminology, 
since  this  will  serve  to  convey  the  somewhat  im- 
portant distinctions  which  it  is  now  my  object  to 
express. 

h\  the  foregoing  paragraphs,  under  heading  (A),  we 
have  seen  that  there  must  be  "  literally  numberless 
forms"  which  have  been  ranked  as  true  species, 
whose  diagnostic  characters  are  nevertheless  not 
congenital.  In  the  case  of  plants  especially,  we  know 
that  there  must  be  large  numbers  of  named  species 
which  do  not  conform  to  the  criterion  of  Heredity, 
although  we  do  not  know  which  species  they  are. 
For  present  purposes,  however,  it  is  enough  for  us 
to  know  that  there  are  many  such  named  species, 
where  some  change  of  environment  has  acted  directly 
and  similarly  on  all  the  individual  "  somas  "  exposed 
to  it,  without  affecting  their  "germ-plasms,"  or  the 
material  bases  of  their  hereditary  qualities.  For  named 
species  of  this  kind  we  may  employ  the  term  somato- 
geneiic  species. 

But  now,  if  there  are  any  cases  where  a  change  of 
environment  does  act  on  the  germ-plasms  exposed  to 
it,  the  result  would  be  what  we  may  call  bias  to- 
genetic  species — i.  e.  species  which  conform  to  the 
criterion  of  Heredity,  and  would  therefore  be  ranked 
by  all  naturalists  as  "  true  species."      It  would  not 


toned 
/ever. 
;come 
e,  and 
line, 

ws,  it 
Dlogy, 
Lt  im- 
ect  to 

A),  we 
Dcrless 
pecies, 
5S    not 
;  know 
species 
redity, 
;y  are. 
for  us 
pecies, 
lirectly 
xposed 
or  the 
named 
somato- 

mge  of 

osed  to 

hlasto- 

to    the 

ranked 

uld  not 


Characters  as  Adaptive  and  Specific.    243 

signify  in  such  a  case  whether  the  changed  con- 
ditions of  life  first  affected  the  soma,  and  then,  through 
changed  nutrition,  the  germ-plasm ;  or  whether 
from  the  first  it  directly  affected  the  germ-plasm  itself. 
For  in  either  case  the  result  would  be  a  "  species," 
which  would  continue  to  reproduce  its  peculiar 
features  by  heredity. 

Now,  the  supposition  that  changed  conditions  of  life 
may  thus  affect  the  congenital  endowments  of  germ- 
plasm  is  not  a  gratuitous  one.  The  sundry  facts 
already  given  in  previous  chapters  are  enough  to 
show  that  the  origin  of  a  blastogenetic  species  by  the 
direct  action  on  germ-plasm  of  changed  conditions 
of  life  is,  at  all  events,  a  possibility.  And  a  little 
further  thought  is  enough  to  show  that  this  possibility 
becomes  a  probability — if  not  a  virtual  certainty. 
Even  Weismann — notwithstanding  his  desire  to  main- 
tain, as  far  as  he  possibly  can,  the  *' stability"  of 
germ-plasm — is  obliged  to  allow  that  external  con- 
ditions acting  on  the  organism  may  in  some  cases 
modify  the  hereditary  qualities  of  its  germ-plasm,  and 
so,  as  he  says,  "  determine  the  phyletic  development 
of  its  descendants."  Again,  we  have  seen  that  he  is 
compelled  to  interpret  the  results  ot  'lis  own  experi- 
ments on  the  climatic  varieties  of  certain  butterflies 
by  saying,  "  I  cannot  explain  the  facts  otherwise  than 
by  supposing  the  passive  acquisition  of  characters 
produced  by  direct  influences  of  climate  " ;  by  which 
he  means  that  in  this  case  the  influence  of  climate 
acts  directly  on  the  hereditary  qualities  of  germ- 
plasm.     Lastly,  and  more  generally,  he  spys : — 

"  But  although  I  hold  it  improbable  that  individual  variability 
can  depend  on  a  direct  action  of  external  influences  upon  the 

R  a 


'i 


iti 


'I 


I 


^1 


244         Darwin,  and  after  Darwin. 


\ ' '  '■■  * 


"«, 


it    •       A: 


i 


germ  cells  and  their  contained  germ-plasm,  because — as 
follows  from  sundry  facts— the  molecular  structure  of  the 
germ-plasm  must  be  very  difficult  to  change,  yet  it  is  by  no 
means  to  be  implied  that  this  structure  may  not  possibly  be 
altered  by  influences  of  the  same  kind  continuing  for  a  very 
long  time.  Thus  it  seems  to  me  the  possibility  is  not  to  be 
rejected,  that  influences  continued  for  a  long  time,  that  is, 
for  generations,  such  as  temperature,  kind  of  nourishment, 
&c.,  which  may  aflect  the  germ-cells  as  well  as  any  other 
part  of  the  organism,  may  produce  a  change  in  the  constitu- 
tion of  the  germ-plasm.  But  such  influences  would  not  then 
produce  individual  variation,  but  would  necessarily  modify  in 
the  same  way  all  the  individuals  of  a  species  living  in  a  certain 
district.  It  is  possible,  though  it  cannot  be  proved,  that 
many  climatic  varieties  have  arisen  in  this  manner." 

So  far,  then,  we  have  testimony  to  this  point,  as  it 
were,  from  a  reluctant  witness.  But  if  we  have  no 
theory  involving  the  "stability  of  germ-plasm"  to 
maintain,  we  can  scarcely  fail  to  see  how  susceptible 
the  germ-plasm  is  likely  to  prove  to  changed  con- 
ditions of  life.  For  we  know  how  eminently  sus- 
ceptible it  is  in  this  respect  when  gauged  by  the 
practical  test  of  fertility  ;  and  as  this  is  but  an  expres- 
sion of  its  extraordinarily  complex  character,  it  would 
indeed  be  surprising  if  it  were  to  enjoy  any  immunity 
against  modification  by  changed  conditions  of  life. 
We  have  seen  in  the  foregoing  chapter  how  fre- 
quently and  how  considerably  somatogenetic  changes 
are  thus  caused,  so  as  to  produce  "somatogenetic 
species" — or,  where  we  happen  to  know  that  the 
changes  are  not  hereditary,  "  climatic  varieties."  But 
the  constitution  of  germ-plasm  is  much  more  complex 
than  that  of  any  of  the  structures  which  are  developed 
therefrom.  Consequently,  the  only  wonder  is  that 
hitherto  experimentalists  have  not  been  more  successful 


Characters  as  Adaptive  and  Specific.    245 

in  producing  " blastogcnctic  species"  by  artificial 
changes  of  environment.  Or,  as  Ray  Lankcster  has 
well  stated  this  consideration,  ''  It  is  not  difficult  to 
suggest  possible  ways  in  which  the  changed  con- 
ditions, shown  to  be  important  by  Darwin,  could  act 
through  the  parental  body  upon  the  nuclear  matter 
of  the  egg-cell  and  sperm-cell,  with  its  immensely 
complex  and  therefore  unstable  constitution.  .  .  .  The 
wonder  is,  not  that  [blastogenetic]  variation  occurs, 
but  that  it  is  not  excessive  and  monstrous  in  every 
product  of  fertilization  ^." 

If  to  this  it  should  be  objected  that,  as  a  matter 
of  fact,  experimentalists  have  not  been  nearly  so 
successful  in  producing  congenital  modifications  of 
type  by  changed  conditions  of  life  as  they  have  been 
in  thus  producing  merely  somatic  modifications  ;  or  if  it 
should  be  further  objected  that  we  have  no  evidence 
at  all  in  nature  of  a  "  blastogenetic  species  "  having 
been  formed  by  means  of  climatic  influences  alone, — 
if  these  objections  were  to  be  raised,  they  would  admit 
of  the  following  answer. 

With  regard  to  experiments,  so  few  have  thus  far 
been  made  upon  the  subject,  that  objections  founded 
on  their  negative  results  do  not  carry  much  weight — 
especially  when  we  remember  that  these  results  have 
not  been  uniformly  negative,  but  sometimes  positive, 
as  shown  in  Chapter  VI.  With  regard  to  plants  and 
animals  in  a  state  of  nature,  the  objection  is  wholly 
futile,  for  the  simple  reason  that  in  as  many  cases  as 
changed  conditions  of  life  may  have  caused  an  here- 
ditary change  of  specific  type,  there  is  now  no  means 

'  Aature,J)&(i.  la,  18S9,  P-  129. 


W 


,^' 


246         Darwifif  and  aftei  Darwin, 


% ' 


r.,,, 

",  ■  'Ml 


s 


"H 


!  i 


ill' 


■'iij 


of  obtaining  "  evidence "  -pen  the  subject.  But  Are 
are  not  on  this  account  entitled  to  conclude  against 
the  probpbility  of  such  changes  of  specific  type 
having  been  more  or  less  frequently  thus  produced. 
And  still  less  can  we  be  on  this  account  entitled  to 
c  .'idr.  against  the  possibility  of  such  a  change 
havi«;;  c'^er  occurred  in  any  single  instance.  Yet 
this  wiipt  must  be  concluded  by  any  one  who 
maintains  tiia';  the  origin  of  all  species — and,  a  for- 
tiori^ of  all  specific  characters — must  necessarily  have 
been  due  to  natural  selection. 

Now,  if  all  this  be  admitted — and  I  do  not  see  how 
it  can  be  reasonably  questioned — consider  how  in:  por- 
tant  its  bearing  becomes  on  the  issue  before  us.  If 
germ-plasm  (using  this  term  for  whatever  it  is  that 
constitutes  the  material  basis  of  heredity)  is  ever 
capable  of  having  its  congenital  endowments  altered 
by  the  direct  action  of  external  conditions,  the  result- 
ing change  of  hereditary  characters,  whatever  else 
it  may  be,  need  not  be  an  adaptive  change.  Indeed, 
according  to  Weismann's  theory  of  germ-plasm,  the 
chances  must  be  infinitely  against  the  change  being 
an  adaptive  one.  On  the  theory  of  pangenesis — that 
is  to  say,  on  the  so-called  Lamarckian  principles — 
there  would  be  much  more  reason  for  entertaining  the 
possibly  adaptive  character  of  hereditary  change  due 
to  the  direct  action  of  the  environment.  Therefore 
we  arrive  at  this  curious  result.  The  more  that  we  are 
disposed  to  accept  Weismann's  theory  of  heredity,  and 
with  it  the  corollary  that  natural  selection  is  the  sole 
cause  of  adaptive  modification  in  species,  the  less  are 
we  entitled  to  assume  that  all  specific  characters 
must  necessarily  be  adaptive.     Seeing  that  in  nature 


Characters  as  Adaptive  and  Specific.    247 

there  are  presumably  many  cases  like  those  of  Hoff- 
mann's plants,  Weismann's  butterflies,  &c.,  where  the 
hereditary  qualities  of  germ-plasm  have  (on  his  hypo- 
thesis) been  modified  by  changed  conditions  of  life, 
we  are  bound  to  believe  that,  in  all  cases  where  such 
changes  do  not  happen  to  be  actively  deleterious, 
they  will  persist.  And  inasmuch  as  characters  which 
are  only  of  '•  specific  "  value  must  be  the  characters 
most  easily — and  therefore  most  frequently — induced 
by  any  slight  changes  in  the  con. ';it>  ion  of  germ- 
plasm,  while,  for  the  same  reasr  (u  lely,  that  of 
their  trivial  nature)  they  are  '  .si,  likely  to  prove 
injurious,  it  follows  that  the  less  /e  believe  in  the 
functionally-produced  adaptal  s  of  Lamarck,  the 
more  ought  we  to  resist  the  assumption  that  all 
specific  characters  must  necessarily  be  adaptive 
characters. 


I 


•5 


Upon  the  whole,  then,  and  with  regard  to  the 
direct  action  of  external  conditions,  I  conclude— not 
only  from  general  considerations,  but  also  from  special 
facts  or  instances  quite  sufficient  for  the  purpose — 
that  these  must  certainly  give  rise  to  immense  num- 
bers of  somatogenetic  species  on  the  one  hand,  and 
probably  to  considerable  numbers  of  blastogenetic 
species  on  the  other ;  that  in  neither  case  is  there  any 
reason  for  supposing  the  distinctively  "  specific  char- 
acters "  to  be  other  than  "  neutral "  or  "  indifferent"; 
while  there  are  the  best  of  reasons  for  concluding  the 
contrary.  So  that,  under  this  division  of  our  subject 
alone  (B).  there  appears  to  be  ample  justification 
for  the  statement  that  ''  a  large  proportional  number 
of  specific  characters  "  are  in  reality,  as  they  are  in 


^^r 


'^frF 


f' 

K-; 


'"► 


t'S 


■"H'< 


1 


If 


„  '1! 
'I 


•\ 


rat.    i',j 


248         Darwin,  and  after  Darwin, 

ippearnncc,  destitute  of  significance  from  a  utilitarian 
point  of  view. 

(C.) 

Thus  far  in  the  present  chapter  we  have  been 
dealing  exclusively  with  the  case  of  "climatic  varia- 
tion,' or  change  of  specific  type  due  to  changes  in 
the  external  conditions  of  life.  But  it  will  be  remem- 
bered that,  in  the  preceding  chapter,  allusion  was 
likewise  made  to  changes  of  specific  type  due  to 
internal  causes  or  to  what  Darwin  has  called  "  the 
nature  of  the  organism."  Under  this  division  of 
our  subject  I  mentioned  especially  Sexual  Selection, 
which  is  supposed  to  arise  in  the  aesthetic  taste 
of  animals  themselves  ;  Isolation,  which  is  supposed 
to  originate  new  types  by  allowing  the  average 
characters  of  an  isolated  section  of  an  old  type  to 
develop  a  new  history  of  varietal  change,  as  we  shall 
see  more  fully  in  the  ensuing  part  of  this  treatise  ; 
and  the  Laws  of  Growth,  which  is  a  general  term  for 
the  operation  of  unknown  causes  of  change  incidental 
to  the  living  processes  of  organisms  which  present  the 
change. 

Now,  under  none  of  these  divisions  of  our  subject 
can  there  be  any  question  touching  the  criterion  of 
Heredity.  For  if  new  species — or  even  single  specific 
characters  of  new  species — are  ever  produced  by  any 
of  these  causes,  they  muct  certainly  all  "  reproduce 
their  like."  Therefore  the  only  question  which  can 
here  obtain  is  as  to  whether  or  not  such  causes  ever  do 
originate  new  species,  or  even  so  much  as  new  specific 
characters.  Mr.  Wallace,  though  not  always  consis- 
tently, answers  this  question  in  the  negative ;  but  the 


Characters  as  Adaptive  and  Specific.    249 

great  majority  of  naturalists  follow  Darwin  by  answering 
it  in  the  affiinialivc.  And  this  is  enough  to  show  the 
only  point  which  we  need  at  present  concern  ourselves 
with  showing — viz.  that  the  question  is,  at  the  least, 
an  open  one.  I^'or  as  long  as  this  question  is  an  open 
one  among  believers  in  the  theory  of  natural  selection, 
it  must  clearly  be  an  unwarrantable  deduction  from 
that  theory,  that  all  species,  and  a  fortiori  all  specific 
characters,  are  necessarily  due  to  natural  selection. 
The  deduction  cannot  be  legitimately  drawn  until 
the  possibility  of  any  other  cause  of  specific  modifica- 
tion has  been  excluded.  But  the  bare  fact  of  the 
question  as  just  stated  being  still  and  at  the  least  an 
open  question,  is  enough  to  prove  that  this  possibility 
has  not  been  excluded.  Therefore  the  deduction  must 
be,  again  on  this  ground  alone  (C),  unwarrantable. 


Such  are  my  several  reasons — and  it  is  to  be 
observed  that  they  are  all  independent  reasons — foi 
concluding  that  it  makes  no  practical  difference  to 
the  present  discussion  whether  or  not  we  entertain 
Heredity  as  a  criterion  of  specific  distinction.  Seeing 
that  our  species- makers  have  paid  so  little  regard  to 
this  criterion,  it  is  neither  absurd  nor  preposterous 
to  have  adduced,  in  the  preceding  chapter,  the  facts 
of  climatic  variation.  On  the  contrary,  as  the  defini- 
tion of'  species"  which  has  been  practically  followed 
by  our  species-makers  in  No.  3,  and  not  No.  4,  these 
facts  form  part  and  parcel  of  our  subject.  It  is  per- 
fectly certain  that,  in  the  vegetable  kingdom  at  all 
events,  '"  a  large  proportional  number  "  of  specifically 
diagnostic  characters  would  be  proved  by  experiment 
to  be  "  somatogenetic  " ;    while  there  are  numerous 


i 


250         Darwin,  and  after  Darwin. 

constant  characters  classed  as  varietal,  although  it  is 
well  known  that  they  are  "  blastogenetic."  Moreover, 
we  can  scarcely  doubt  that  many  specific  characters 
which  are  also  hereditary  characters  owe  their  exist- 
ence, not  to  natural  selection,  but  to  the  direct  action 
of  external  causes  on  the  hereditary  structure  of 
"  germ-plasm " ;  while,  even  apart  from  this  con- 
sideration, there  are  at  least  three  distinct  and  highly 
general  principles  of  specific  change,  which  are  ac- 
cepted by  the  great  majority  of  Darwinists,  and  the 
only  common  peculiarity  of  which  is  that  they  pro- 
duce hereditary  changes  of  specific  types  without  any 
reference  to  the  principle  of  utility. 


m 


!ilf 


lil 


CHAPTER  X. 

Characters  as  Adaptive  and  Speciitc 

(concluded). 

Our  subject  is  not  yet  exhausted.  For  it  remains 
to  observe  the  consequences  which  arise  from  the 
dogma  of  utility  as  the  only  yaison  d'Hre  of  species, 
or  of  specific  characters,  when  this  dogma  is  applied 
in  practice  by  its  own  promoters. 

Any  definition  of  "species" — excepting  Nos.  i,  a, 
and  5,  which  may  here  be  disregarded — must  needs 
contain  some  such  phrase  as  the  one  with  which  Nos.  3 
and  4  conclude.  This  is,  that  peculiar  characters,  in 
order  to  be  recognized  as  of  specific  value,  must 
present  neither  more  nor  less  than  "some  certain 
degree  of  distinctness."  If  they  present  more  than 
this  degree  of  distinctness,  the  form,  or  forms,  in 
question  must  be  ranked  as  generic ;  while  if  they 
present  less  than  this  degree  of  distinctness,  they 
must  be  regarded  as  varietal — and  this  even  if 
they  are  known  to  be  mutually  sterile.  What, 
then,  is  this  certain  degree  of  distiiictness?  Waat 
are  its  upper  and  lower  limits.?  This  questioi^  is 
one  that  cannot  be  answered.  From  the  very 
nature    of   the    case    it     is    impossible    to    find    a 


u 


jAP{ 


•fcr 


252         Darwin,  and  after  Darwin. 


^^ 


\ 
1''-' 

V: 


I,  V 


h». 


"'»•» 

•'^!, 


*«;:! 

s 


uniform  standard  of  distinction  whereby  to  draw 
our  boundary  lines  between  varieties  and  species 
on  the  one  hand,  or  between  species  and  genera  on 
the  other.  One  or  two  quotations  will  be  sufficient 
to  satisfy  the  general  reader  upon  this  point. 

Mr.  Wallace  himself  alludes  to  "the  great  diffi- 
culty that  is  felt  by  botanists  in  determining  the 
limits  of  species  in  many  large  genera,"  and  gives 
as  examples  well-known  instances  where  systematic 
botanists  of  the  highest  eminence  differ  hopelessly 
in  their  respective  estimates  of  "  specific  characters." 
Thus : — 

"  Mr.  Baker  includes  under  a  single  species,  Rosa  canina, 
no  less  than  twenty-eight  named  varieties  distinguished  by 
more  or  less  constant  characters,  and  often  confined  to  special 
localities,  and  to  these  are  referred  about  seventy  of  the 
species  of  British  and  continental  botanists.  Of  the  genus 
Rubus  or  brcimble,  five  British  species  are  given  in  Bentham's 
Handbook  of  British  Floya^  while  in  the  fifth  edition  of 
Babington's  Manual  of  Biitish  Botany^  published  about  the 
same  time,  no  less  than  forty-five  species  are  described.  Of 
willows  (Salix)  the  same  two  works  enumerate  fifteen  and 
thirty-one  species  respectively.  The  hawkweeds  (Hieracium) 
are  equally  puzzling,  for  while  Mr.  Bentham  admits  only  seven 
British  species,  Professor  Babington  describes  no  less  than 
seventy-two,  besides  several  named  varieties '." 


'    1 

s    :     \ 

«: 

flj' 

Mr.  Wallace  goes  on  to  quote  further  instances, 
such  as  that  of  Draba  verna.  which  Jordan  has 
found  to  present,  in  the  south  of  France  alone,  no  less 
than  fifty-two  permanent  varieties,  which  all  "come 
true  from  seed,  and  thus  present  all  the  character- 
istics of  a  tri'e  species";    so  that,  "as  the   plant    is 

'  Darwinism,  p.  77. 


4  ■  .!;■ 


^' 


I 


vl 


{.haraders  as  Adaptive  and  Specific.   253 

very  common  almost  all  over  Europe,  and  ranges 
from  North  America  to  the  Himalayas,  the  number 
of  similar  forms  over  this  wide  area  would  probably 
have  to  be  reckoned  by  hundreds,  if  not  by  thou- 
sands ^" 

One  or  two  further  quotations  may  be  given  to 
the  same  general  effect,  selected  from  the  writings  of 
specialists  in  their  several  departments. 

"  There  is  nothing  that  divides  systcmatists  more  than  what 
constitutes  a  genus.  Species  that  resemble  each  other  more  than 
other  species,  is  perhaps  the  best  definition  that  can  be  given. 
This  is  obviously  an  uncertain  test,  much  depending  on 
individual  judgement  and  experience ;  but  that,  in  the  evolu- 
tion of  forms,  such  difficulties  should  arise  in  the  limitation 
of  genera  and  species  was  inevitable.  What  is  a  generic 
character  in  one  may  be  only  a  specific  character  in  another. 
As  an  illustration  of  the  uncertain  importance  of  characters, 
I  may  mention  the  weevil  genus  Cenirinus,  in  which  the 
leading  characters  in  the  classification  of  the  family  to  wlaich 
it  belongs  are  so  mixed  tha*^  systematists  liave  been  content 
to  keep  the  species  together  in  a  group  that  cannot  be  defined. 
.  .  .  No  advantage  or  disadvantage  is  attached,  apparently, 
to  any  of  the  characters.  There  are  about  200  species,  all 
American. 

The  venation  of  the  wings  of  insects  is  another  example  of 
modifications  without  serving  any  special  purpose.  There  is 
no  vein  in  certain  Thripidae,  and  only  a  rudiment  or  a  single 
vein  in  Chalcididae.  There  are  thousands  of  variations  more 
or  less  marked,  some  of  the  same  type  with  comparatively 
trivial  variation,  others  presenting  distinct  types,  even  in  the 
same  family,  such  genera,  for  example,  as  Polyneura,  Tctii- 
getra,  Huechys^  &c.  in  the  Cicadidae. 

Individual  differences  have  often  been  regarded  as  distinctive 
of  species  ;  varieties  also  are  very  deceptive,  and  races  come 
very  near  to  species.  A  South-American  beetle,  Arescus 
histrio,  has  varieties  of  yellow,  red,  and  black,  or  these  colours 

'  Darwinism,  p.  77. 


:tri!0 


»1 


fv., 


AT 


I, 

If:-.. 


if  ^ 


^11 


254         Darwm,  and  after  Darwin, 

variously  intermixed,  and,  what  is  very  unusual,  longitudinal 
stripes  in  some  and  transverse  bars  in  others,  and  all  taken 
in  the  same  locaHty.  Mr.  A.  G.  Butler,  of  the  British  Museum, 
is  of  opinion  thai  *  what  is  generally  understood  by  the  term 
species  (that  is  to  say,  a  well-defined,  distinct,  and  constant  type, 
having  no  near  allies)  is  non-existent  in  the  Lepidoptera,  and 
that  the  nearest  approach  to  it  in  this  order  is  a  constant,  though 
but  slightly  differing,  rare  or  local  form— that  genera,  in  fact,  con- 
sist wholly  of  a  gradational  series  of  such  forms  (Ann.  Mag.  Nat. 
Hist.  5,  xix.  io3)V" 

So  mucli  as  regards  entomology,  and  still  living 
forms.  In  illustration  of  the  same  principles  in 
connexion  with  palaeontological  series,  I  may  quote 
Wiirtenberger,  who  says  : — 

"With  respect  to  these  fossil  forms  [i.e.  multitudinous  forms 
of  fossil  Amnionites],  it  is  quite  immaterial  whether  a  very 
short  or  a  somewhat  longer  part  of  any  branch  be  dignified  with 
a  separate  name,  and  regarded  as  a  species.  The  prickly 
Ammonites,  classed  under  the  designation  of  Armata,  are  so 
intimately  connected  that  it  becomes  impossible  to  separate  the 
accepted  species  sharply  from  one  another.  The  same  remark 
applies  to  the  group  of  which  the  manifold  forms  are  distin- 
guished by  their  ribbed  shells,  and  are  called  Planulata  ^." 

I  had  here  supplied  a  number  of  similar  quotations 
from  writers  in  various  other  departments  of  systematic 
work,  but  afterwards  struck  them  out  as  superfluous. 
For  it  is  not  to  be  anticipated  that  any  competent 
naturalist  will  nowadays  dispute  that  the  terms 
"variety,"  "species,"  and  "genus"  stand  for  merely 
conventional  divisions,  and  that  whether  a  given  form 
shall  be  ranked  under  one  or  the  other  of  them  is 


^  Pascoe,    The  Darivinian   Theory  of  the   Origin  of  Species,  1891, 
pp.  .^1-33,  and  46. 

'^  Aeiier  Beit  rag  znm  geologischen  Beweis  der  Darwin  schen  'Theorie, 

1873. 


Characters  as  Adaptive  and  Specific.   255 


Ill 


often  no  more  than  a  matter  of  individual  taste. 
From  the  nature  of  the  case  there  can  be  no  objective, 
and  therefore  no  common,  standards  of  delimitation. 
This  is  true  even  as  regards  any  one  given  depart- 
ment of  systematic  work  ;  but  when  we  compare  the 
standards  of  delimitation  which  prevail  in  one  depart- 
ment with  those  which  prevail  in  another,  it  becomes 
evident  that  there  is  not  so  much  as  any  attempt  at 
agreeing  upon  a  common  measure  of  specific  dis- 
tinction. 

But  what,  it  may  well  be  asked,  is  the  use  of  thus 
insisting  upon  well-known  facts,  which  nobody  will 
dispute?  Well,  in  the  first  place,  we  have  already 
seen,  in  the  last  chapter,  that  it  is  incumbent  on  those 
who  maintain  that  all  species,  or  even  all  )ecific 
characters,  must  be  due  to  natural  selection,  to  tell  us 
what  they  mean  by  a  species,  or  by  characters  as 
specific.  If  I  am  told  to  believe  that  tlie  definite 
quality  A  is  a  necessary  attribute  of  B,  and  yet  that 
B  is  ''  not  a  distinct  entity,"  but  an  undcfinable  ab- 
straction, I  can  only  marvel  that  any  one  should 
expect  me  to  be  so  simple.  But,  without  recurring 
to  this  point,  the  use  of  insisting  on  the  facts  above 
stated  is,  in  the  second  place,  that  otherwise  I  cannot 
suppose  any  general  reader  could  believe  them  in  view 
of  what  is  to  follow.  For  he  cannot  but  fetl  that  the 
cost  of  believing  them  is  to  render  inexplicable  the 
mental  processes  of  those  naturalists  who,  in  the  face  of 
such  facts,  have  deduced  the  following  conclusions. 

The  school  of  naturalists  against  which  I  am 
contending  maintains,  as  a  generalization  deduced 
from  the  theory  of  natural  selection,  that  all  species, 
or  even  all  specific  characters,  must  necessarily  owe 


fl^ 


256        Darwm,  and  after  Darwin. 


!   * 
AT 


'!'» 


It,*  Wl 

^..  ■■■■1» 


}1 


I    »,ai,y, 


I- 


their  origin  to  the  principle  of  utility.  Yet  this  same 
school  does  not  maintain  any  such  generalization, 
either  with  regard  to  varietal  characters  on  the  one 
hand,  or  to  generic  characters  on  the  other.  On  the 
contrary.  Professor  Huxley,  Mr.  Wallace,  and  all 
other  naturalists  who  agree  with  them  in  refusing  to 
entertain  so  much  as  the  abstract  possibility  of  any 
cause  other  than  natural  selection  having  been  pro- 
ductive of  species,  fully  accept  the  fact  of  other 
causes  having  been  largely  concerned  in  the  production 
of  varieties,  genera,  families,  and  all  higher  groups, 
or  of  the  characters  severally  distinctive  of  each. 
Indeed,  Mr.  Wallace  does  not  question  wl.ut  appears 
to  me  the  extravagant  estimate  of  Professor  Cope, 
that  the  non-adaptive  characters  distinctive  of  those 
higher  groups  are  fully  equal,  in  point  of  numbers,  to 
the  adaptive.  But,  surely,  if  the  theor  •  )f  evolution 
by  natural  selection  is,  as  we  all  gVQt,  u  true  theory 
of  the  origin  of  species,  it  must  likewise  be  a  true 
theory  of  the  origin)  .;;  genera  ;  and  if  it  be  supposed 
essential  to  the  integ'^i'.y  of  the  theory  in  its  former 
aspect  that  all  specific  characters  should  be  held  to 
be  useful,  I  fail  to  see  how,  in  regard  to  its  latter 
aspect,  we  are  so  readily  to  surrender  the  necessary 
usefulness  of  all  generic  characters.  And  exactly  the 
same  remark  applies  to  the  case  of  constant  "varieties," 
where  again  the  doctrine  of  utility  as  universal  is  not 
maintained.  Yet,  according  to  the  general  theory  of 
evolution,  constant  varieties  are  what  Darwin  termed 
"incipient  species,"  while  species  are  what  rr.q.y  be 
termed  *'  incipient  genera."  Therefore,  if  the  di, -trine 
of  utility  as  universal  be  conceded  to  fail  in  the  case 
of  varieties  on  the  one  hand  and  of  genera  on  the 


Characters  as  Adaptive  and  Specific.   257 

other,  where  is  the  consistency  in  maintaining  that  it 
must  "  necessarily  "  liold  as  regards  the  intermediate 
division,  species?  Truly  the  shade  of  Darwin  may 
exclaim.  "  Save  me  from  my  friends."  And  truly 
against  logic  of  this  descri[)tion  a  follower  of  Darwin 
must  find  it  difficult  to  argue.  If  one's  opponcMits 
were  believers  in  special  creation,  and  therefore  stood 
upon  some  definite  ground  while  maintaining  this 
difference  between  species  and  all  other  taxonomic 
divisions,  there  would  at  least  be  some  issue  to  argue 
about.  But  when  on  the  one  hand  it  is  conceded 
that  species  are  merely  arbitrary  divisions,  which 
differ  in  no  respect  as  to  the  process  of  their  evolution 
from  either  varieties  or  genera,  while  on  the  other 
hand  it  is  affirmed  that  there  is  thus  so  great  a 
difference  in  the  result,  all  we  can  say  is  thai  our 
opponents  are  entangling  themselves  in  the  meshes 
of  a  sheer  contradiction. 

Or,  otherwise  stated,  specific  characters  differ  fron* 
varietal  characters  in  being,  as  a  rule,  more  pronovrnced 
and  more  constant:  on  this  account  advoc  tes  of 
utility  as  universal  apply  the  ('octrine  to  spedes, 
while  they  do  not  feel  the  "  nec(  .ty"  of  applying  it 
to  varieties.  But  now,  generic  .nd  all  higher  char- 
acters are  even  more  constant  md  more  pronounced 
than  specific  characters — not  t  >  say,  in  many  cases, 
more  generally  diffused  ov  a  larger  number  of 
organisms  usually  occupying  larger  areas.  There- 
fore, a  fortiori,  if  for  the  reasons  above  stated  evolu- 
tionists regard  it  as  a  necessary  deduction  from  tbv 
theory  of  natural  selection  that  all  specific  char- 
acters must  be  useful,  much  raore  ought  it  to  be 
a  necessary  deduction  from  this  theory  that  all  generic, 

II.  S 


tflif^ 


>.,ll  ft 


I, 


'  I 


II 


■I  ^f 


258         Darwin,  and  after  Darwin. 

and  still  more  all  higher,  characters  must  be  useful. 
But,  as  we;  have  seen,  this  is  not  maintained  by  our 
opponents.  On  the  contrary,  they  draw  the  sharpest 
distinction  between  specific  and  all  other  characters  in 
this  respect,  freely  conceding  that  both  those  below 
and  those  above  them  need  not — and  very  often  do 
not — present  any  utilitarian  significance. 

Although  it  appears  to  me  that  this  doctrine  is  self- 
contradictory,  and  on  this  ground  a'one  might  be 
summarily  dismissed,  as  it  is  now  held  in  one  or 
other  of  its  forms  by  many  naturalists,  I  will  give  it 
a  more  detailed  consideration  in  both  its  parts — 
namely,  first  with  respect  to  the  distinction  between 
varieties  and  species,  and  next  with  respect  to  the 
distinction  between  species  and  genera. 

Until  it  can  be  shown  that  species  are  something 
more  than  merely  arbitrary  divisions,  due  to  the 
disappearance  of  intermediate  varietal  links ;  that  in 
soiree  way  or  another  they  are  ''definite  entities," 
which  admit  of  being  delineated  by  the  application  of 
some  uniform  or  general  principles  of  definition  ; 
that,  in  .short,  species  have  only  then  been  classified 
as  such  when  it  has  been  shown  that  the  origin  of 
each  has  been  due  to  the  operation  of  causes  which 
have  not  been  concerned  in  the  production  of  varieties  ; 
— until  these  things  are  shown,  it  clearly  remains 
a  gratuitous  dogma  to  maintain  that  forms  which 
have  been  called  species  differ  from  forms  which  have 
been  called  varieties  in  the  important  respect,  that 
they  (let  alone  each  of  all  their  distinctive  characters) 
must  necessarily  have  been  due  to  the  principle  of 
utility.     Yet,  as   we   have   seen,   even    Mr.   Wallace 


Characters  as  Adaptive  and  Specific.    259 

allows  that  a  species  is  "not  a  distinct  entity,"  but 
"  an  assemb]ac;"e  of  individuals  which  have  become 
somewhat  modified  in  structure,  form,  and  consti- 
tution";  while  estimates  of  the  kinds  and  dc£;rees 
of  modification  which  are  to  be  taken  as  of  specific 
value  are  conceded  to  be  undefinable,  fluctuating;,  and 
in  not  a  few  cases  almost  ludicrously  divergent. 

Perhaps  one  cannot  more  forcibly  present  the 
rational  value  of  this  position  than  by  notinc,^  the  fol- 
lowing consequences  of  it.  Mr.  Gulick  v/rites  me  that 
while  studying  the  land-shellsof  the  Sandwich  Islands, 
and  finding  there  a  rich  profusion  of  unique  varieties, 
in  cases  where  the  intermediate  varieties  were  rare  he 
could  himself  have  created  a  number  of  species  by 
simply  throwing  these  intermediate  varieties  into  his 
fire.  Now  it  follows  from  the  d(\gma  which  we  are 
considering,  that,  by  so  doing,  not  only  would  he 
have  created  new  species,  but  at  the  same  time 
he  would  have  proved  them  due  to  natural  selection, 
and  endowed  the  diagnostic  characters  of  each  with 
a  "  necessarily  "'  adaptive  meaning-,  which  previously  it 
was  not  necessary  that  they  should  present.  Before 
his  destruction  of  these  intermediate  varieties,  he  need 
have  felt  himself  under  no  obligation  to  assume  that 
any  given  character  at  either  end  of  the  series  was 
of  utilitarian  significance  :  but,  after  his  destruction  of 
the  intermediate  forms,  he  could  no  longer  entertain 
any  question  upon  the  matter,  under  pain  of  being 
denounced  as  a  Darwinian  heretic. 

Now  the  application  is  self-evident.  It  is  a  general 
fact,  which  admits  of  no  denial  that  the  more  our 
knowledge  of  any  flora  or  fauna  increases,  the  greater 
is    the    number    of    intermediate    forms    which    are 

S  2 


;rj 


26o 


Darwin^  and  after  Darzvin. 


I 


h 


i  * 


brouj^ht  to  light,  either  as  still  existing  or  as  having 
once  existed.  Consequently,  the  more  that  such 
knowledge  increases,  the  more  does  our  catalogue  of 
'•  species  "  diminish.  As  Kerner  says,  '•  bad  species  " 
are  always  multiplying  at  the  expense  of  "good 
species  "  ;  or,  as  Oscar  Schmidt  (following  Hackel) 
similarly  remarks,  if  we  could  know  as  much  about 
the  latter  as  we  do  about  the  former,  '•  all  species, 
without  any  exception,  would  become  what  species- 
makers  understand  by  '  bad  species  '  ^"  Hence  we 
see  that,  just  as  Mr.  Gulick  could  have  created  good 
species  by  secretly  destroying  his  intermediate 
varieties;  so  has  Nature  produced  her  ''  good  species  " 
for  the  delectation  of  systematists.  And  just  as  Mr. 
Gulick,  by  first  hiding  and  afterwards  revealing  his 
intermediate  forms,  could  have  made  the  self-same 
characters  in  the  first  instance  necessarily  useful,  but 
ever  afterwards  presumably  useless,  so  has  Nature 
caused  the  utility  of  diagnostic  characters  to  vary 
with  our  knowledge  of  her  intermediate  forms.  It 
belongs  to  the  essence  of  our  theory  of  descent,  that 
in  all  cases  these  intermediate  forms  must  either  be 
now  existing  or  have  once  existed  ;  and,  therefore, 
that  the  work  of  species-makers  consists  in  nothing 
more  than  marking  out  the  lacunae  in  our  knowledge 
of  them.  Yet  we  are  bound  to  believe  that  wherever 
these  lacunae  in  our  knowledge  occur,  there  occurs 
also  the  objective  necessity  of  causation  as  utilitarian 
— a  necessity,  however,  which  vanishes  so  soon  as 
our  advancing  information  supplies  the  intermediate 
forms  in  question.    It  may  indeed  appeal  strange  that 


The  Doctrine  of  Descent  and  Darwinism,  Eng.  Trans,  p.  loa. 


Characters  as  Adaptive  and  Specific.    261 

the  utility  or  non-utility  of  orgcinic  structures  should 
thus  depend  on  the  accidents  of  human  knowledge; 
but  this  is  the  Darwinian  faith,  and  he  who  doubts  the 
dogma  is  to  be  anathema. 

Turning  next  to  the  similar  distinction  which  it 
is  sought  to  draw  between  species  and  genera,  here 
it  will  probably  be  urged,  as  I  understand  it  to 
be  urged  by  Mr.  Wallace,  that  generic  characters 
(and  still  more  characters  of  families,  orders,  &c.)  refer 
back  to  so  remote  a  state  of  things  that  utility 
may  have  been  present  at  their  birth  which  has 
disappeared  in  their  maturity.  In  other  words,  it 
is  held  that  all  generic  characters  were  originally 
specific  characters ;  that  as  such  they  were  all  origin- 
ally of  use  ;  but  that,  after  having  been  rendered 
stable  by  heredity,  many  of  them  may  have  ceased 
to  be  of  service  to  the  descendants  of  those  species 
in  which  they  originated,  and  whose  extinction  has 
now  made  it  impossible  to  divine  what  that  service 
may  have  been. 

Now,  in  the  first  place,  this  is  not  the  interpretation 
adopted  by  Darwin.  For  instance,  he  expressly 
contrasts  such  cases  with  those  of  vestigial  or  "  rudi- 
mentary "  "structures,  pointing  out  that  they  differ 
from  vestigial  structures  in  respect  of  their  perma- 
nence. One  quotation  will  be  sufficient  to  establish 
the  present  point. 

"A  structure  which  has  been  developed  through  long-con- 
tinued selection,  when  it  ceases  to  be  of  service  to  a  species, 
generally  becomes  variable,  as  we  see  with  rudimentary  organs, 
for  it  will  no  longer  be  regulated  by  this  same  power  of 
selection.  But  when,  from  the  nature  of  the  organism  xnd 
of  the  conditions,  moditications  have  been  induced  which  are 


262         DarzviUj  and  after  Darzvin. 


h 


I 


I   "    '1  ' 


I  I  •  4  ^   * 


m'j 


•1 


unimportant  for  the  welfrirc  of  the  si  cries,  they  may  be,  and 
apparently  often  have  been,  transmitted  in  nearly  the  same 
state  to  numerous,  otherwise  modified,  descendants'." 

Here,  and  in  the  context,  we  have  a  sufficiently 
clear  statement  of  Darwin's  view — first,  that  unadap- 
tive  characters  may  arise  in  species  as  "  fluctuating 
variations,  which  sooner  or  later  become  co7istani 
through  the  nature  of  the  organism  and  of  surround- 
ing conditions,  as  well  as  through  the  intercrossing 
of  distinct  individuals,  but  not  through  natural  selec- 
tion "  ^ ;  second,  that  such  unadaptive  characters  may 
then  be  transmitted  in  this  their  stable  condition  to 
species-progeny,  so  as  to  become  distinctive  of  genera, 
families,  &c.  ;  third,  that,  on  account  of  such  characters 
not  being  afterwards  liable  to  diverse  adaptive 
modifications  in  different  branches  of  the  species- 
progeny,  they  are  of  more  value  as  indicating  lines 
of  pedigree  than  are  characters  which  from  the  first 
have  been  useful  ;  and,  lastly,  they  are  therefore  now 
empirically  recognized  by  systematists  as  of  most 
value  in  guiding  the  work  of  classification.  To  me 
it  appears  that  this  view  is  not  only  perfectly  rational 
in  itself,  but  likewise  fully  compatible  with  the  theory 
of  natural  selection — which,  as  I  have  previously 
shown,  is  primarily  a  theory  of  adaptive  characters, 
and  therefore  not  necessarily  a  theory  of  all  specific 
characters.  But  to  those  who  think  otherwise,  it 
must  appear — and  does  appear — that  there  is  some- 
thing wrong  about  such  a  view  of  the  case — that 
it  was  not  consistent  in  the  author  of  the  Origin  of 
Species  thus  to  refer  non-adaptive  generic  characters 
to   a  parentage  of  non-adaptive  specific   characters. 

^  Origin  of  Species ^  p.  175.  '  Ibid.  p.  176  :  italics  mine. 


Characters  as  Adaptive  and  Specific.   263 

Nevertheless,  as  a  matter  of  fact,  Darwin  was  perfectly 
consistent  in  putting  forth  this  view,  because,  unlike 
Wallace,  he  was  not  under  the  sway  of  any  antecedent 
dogma  erroneously  deduced  from  the  theory  of 
natural  selection. 

Next,  without  reference  to  Darwin's  authority,  let 
us  see  for  ourselves  where  the  inconsistency  really  lies. 
T'^  allow  that  generic  characters  may  be  useless,  while 
uenying  that  specific  characters  can  ever  be  so  (unless 
correlated  with  others  that  are  useful),  involves  an 
appeal  to  the  argument  from  igiionmce  touching 
the  ancestral  habits,  life-conditions,  &c.,  of  a  parent 
species  now  extinct.  Well,  even  upon  this  assumption 
of  utility  as  obsolete,  there  remains  to  be  exi)laincd  the 
"stability"  of  useless  characters  now  distinctive  of 
genera,  families,  orders,  and  the  rest.  We  know  that 
specific  characters  which  have  owed  their  origin  to 
utility  and  have  afterwards  ceased  to  present  utility, 
degenerate,  become  variable,  inconstant,  "rudimen- 
tary," and  finally  disappear.  Why,  then,  should  these 
things  not  happen  with  regard  to  useless  generic 
distinctions  ?  Still  more,  why  should  they  not  happen 
with  regard  to  family,  ordinal,  and  class  distinctions? 
On  the  lines  against  which  I  am  arguing  it  would 
appear  impossible  that  any  answer  to  this  question 
can  be  suggested.  For  what  explanation  can  be 
given  of  the  contrast  thus  presented  between  the 
obsolescence  of  specific  characters  where  previous 
utility  is  demonstrable  and  the  permanence  of 
higher  characters  whose  previous  utility  is  assumed? 
As  we  have  already  seen,  Mr.  Wallace  himself 
employs  this  consideration  of  permanence  and  con- 
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264         Darwin,  and  after  Darwin. 

natural  selection  can  have  been  concerned  in  the 
origin  and  maintenance  of  specific  characters.  But 
he  does  not  seem  to  see  that  the  consideration  cuts 
two  ways — and  much  more  forcibly  against  his 
views  than  in  favour  of  them.  For  while,  as  already 
shown  in  the  chapter  before  last,  it  is  sufficiently 
easy  to  dispose  of  the  consideration  as  Wallace  uses 
it  (by  simply  pointing  out  with  Darwin  that  any 
causes  other  than  natural  selection  which  may  have 
been  concerned  in  the  genesis  of  specific  characters, 
must,  if  equally  uniform  in  their  operation,  equally 
give  rise  to  permanence  and  constancy  in  their  results) ; 
on  the  ether  hand,  it  becomes  impossible  to  explr.in 
the  stability  of  useless  generic  characters,  if  as 
Wallace's  use  of  the  argument  requires,  natural  selec- 
tion is  the  only  possible  cause  of  stability.  The 
argument  is  one  that  cannot  be  played  with  fast 
and  loose.  Either  utility  is  the  sole  condition  to 
the  stability  of  any  diagnostic  character  (in  which 
case  it  is  not  open  to  Mr.  Wallace  to  assume  that 
all  generic  or  higher  characters  which  are  uow  use- 
less have  owed  their  origin  to  a  past  utility)  ;  or 
else  utility  is  not  the  sole  condition  to  stability 
(in  which  case  his  use  of  the  present  argument  in 
relation  to  specific  characters  collapses).  We  have 
seen,  indeed,  in  the  chapter  before  last,  that  his  use 
of  the  argument  collapses  anyhow,  or  quite  irrespec- 
tive of  his  inconsistent  attitude  towards  generic 
characters,  with  which  we  were  not  then  concerned. 
But  the  point  now  is  that,  as  a  mere  matter  of  logic, 
the  argument  from  stability  as  Wallace  applies  it 
to  the  case  of  specific  characters,  is  incompatible 
with    his  argument    that    useless   generic   characters 


the 

But 

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his 

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ently 

uses 


Characters  as  Adaptive  and  Specific.   265 

may  originally  have  been  useful  specific  characters. 
It  can  scarcely  be  questioned  that  the  transmuta- 
tion of  a  species  into  a  genus  must,  as  a  rule,  have 
allowed  time  enough  for  a  newly  acquired — i.e. 
peculiar  specific-character — to  show  some  signs  of 
undergoing  degeneration,  if,  as  supposed,  the  original 
cause  of  its  development  and  maintenance  was  with- 
drawn when  the  parent  species  began  to  ramify  into  its 
species-progeny.  Vet,  as  Darwin  says,  "  it  is  notorious 
that  specific  characters  are  more  variable  than 
generic  ^"  So  that,  upon  the  whole,  I  do  not  see 
how  on  grounds  of  general  reasoning  it  is  logically 
possible  to  maintain  Mr.  Wallace's  distinction  between 
specific  and  generic  characters  in  respect  of  necessary 
utility. 

But  now,  and  lastly,  we  shall  reach  the  same 
conclusion  if,  discarding  all  consideration  of  general 
principles  and  formal  reasoning,  we  ^asten  attention 
upon  certain  particular  cases,  or  concrete  facts. 
Thus,  to  select  only  two  illustrations  within  the 
limits  of  genera,  it  is  a  diagnostic  feature  of  the 
genus  Equus  that  small  warty  callosities  occur  on 
the  legs.  It  is  impossible  to  suggest  any  useful 
function  that  is  now  discharged  by  these  callo- 
sities in  any  of  the  existing  species  of  the  genus. 
If  it  be  assumed  that  they  must  have  been  of 
some  use  to  the  species  from  which  the  genus 
originaD.y  sprang,  the  assumption,  it  seems  to  me, 
can  only  be  saved  by  further  assuming  that  in  existing 
species  of  the  genus  these  callosities  are  in  a  vesti- 
gial condition — i.  e.  that  in  the  original  or  parent 
species  they  performed  some  function  which  is  now 

•  Origin  of  Species,  p.  laa. 


266         Darwiriy  and  after  Darwin. 


'(! 


1. 


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II 


obsolete.  But  against  these  assumptions  there  lies 
the  following  fact.  The  callosities  in  question  are 
not  similarly  distributed  through  all  existing  species 
of  the  genus.  The  horse  has  them  upon  all 
his  four  legs,  while  other  species  have  them  only 
upon  two.  Therefore,  if  all  specific  characters  are 
necessarily  due  to  natural  selection,  it  is  manifest 
that  these  callosities  are  not  now  vestigial :  on  the 
contrary,  they  w^^j/ still  be— or,  at  best,  have  recently 
been — of  so  much  importance  to  all  existing  species 
of  the  genus,  that  not  only  is  it  a  matter  of  selection- 
value  to  all  these  species  that  they  should  possess 
these  callosities  ;  but  it  is  even  a  matter  of  selection- 
value  to  a  horse  that  he  should  possess  four  of 
them,  while  it  is  equally  a  matter  of  selection-value 
to  the  ass  that  he  should  possess  only  two.  Here, 
it  seems  to  me,  we  have  once  more  the  doctrine  of 
the  necessary  utility  of  specific  characters  reduced 
to  an  absurdity  ;  while  at  the  same  time  we  display 
the  incoherency  of  the  distinction  between  specific 
characters  and  generic  characters  in  respect  of  this 
doctrine.  For  the  distinction  in  such  a  case  amounts 
to  saying  that  a  generic  character,  if  evenly  distributed 
among  all  the  species,  need  not  be  an  adaptive 
character  ;  whereas,  if  any  one  of  the  species  presents 
it  in  a  slightly  different  form,  the  character  must 
be,  on  this  account,  necessarily  adaptive.  In  other 
words,  the  uniformity  with  which  a  generic  character 
occurs  among  the  species  of  the  genus  is  taken  to 
remove  that  character  from  the  necessarily  useful 
class,  while  the  absence  of  such  uniformity  is  taken 
as  proof  that  the  character  must  be  placed  within 
the  necessarily  useful  class.     Which  is  surely  no  less 


!•'■ ' 


'^ 


\'    1 


Characters  as  Adaptive  and  Specific.   26-] 

a  reductio  ad  absurdtim  with  regard  to  the  generic 
character  than  the  one  just  presented  with  regard  to 
its  variants  as  specific  characters.  And,  of  course, 
this  twofold  absurdity  is  presented  in  all  cases  where 
a  generic  character  is  unequally  distributed  among 
the  constituent  species  of  a  genus. 

But  here  is  an  illustration  of  another  class  of  cases. 
Mr.  Tomes  has  shown  that  the  molar  teeth  of  the 
Orang  present  an  extraordinary  and  altogether  super- 
fluous amount  of  attachment  in  their  sockets — the  fangs 


Fig.  4. — I-ower  Teeth  of  Orang  (after  Tomes). 

being  not  only  exceedingly  long,  and  therefore  deeply 
buried  in  the  jaw-bone,  but  also  curving  round  one 
another,  so  as  still  further  to  strengthen  the  whole  V 
In  the  allied  genera  of  anthropoid  apes  there  is  no 
such  abnormal  amount  of  attachment.  Now,  the 
question  is,  of  what  conceivable  use  can  it  ever 
have  been,  either  to  the  existing  genus,  or  to  its 
parent  species,  that  such  an  abnormal  amount  of 
attachment  should  obtain?  It  certainly  is  not  re- 
quired to  prevent  dislocation  of  the  teeth,  seeing  that 
in  all  allied  genera,  and   even   in   man    himself,  the 

'  A  Manual  of  Dental  Anatomy,  p.  455. 


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268         Danvin,  and  after  Darwin. 

amount  of  attachment  is  already  so  great  that  teeth 
will  break  before  they  can  be  drawn  by  anything 
short  of  a  dentist's  forceps.  Therefore  I  conclude 
that  this  peculiarity  in  the  dentition  of  the  genus 
must  have  arisen  in  its  parent  species  by  way 
of  what  Darwin  calls  a  "fluctuating  variation,'  with- 
out utilitarian  significance.  And  I  adduce  it  in 
the  present  connexion  because  the  peculiarity  is  one 
which  is  equally  unamenable  to  a  utilitarian  ex- 
planation, whether  it  happens  to  occur  as  a  generic 
or  a  specific  character. 

Numberless  similar  cases  might  be  quoted  ;  but 
probably  enough  has  now  been  said  to  prove  the 
inconsistency  of  the  distinction  which  our  opponents 
draw  between  specific  and  all  higher  characters 
in  respect  of  utility.  In  point  of  fact,  a  very 
little  thought  is  enough  to  show  that  no  such 
distinction  admits  of  being  drawn ;  and,  therefore, 
that  any  one  who  maintains  the  doctrine  of  utility 
as  universal  in  the  case  of  specific  characters,  must 
in  consistency  hold  to  the  same  doctrine  in  the  case 
of  generic  and  all  higher  characters.  And  the  fact 
that  our  opponents  are  unable  to  do  this  becomes 
a  virtual  confession  on  their  part  of  the  futility  of 
the  generalization  which  they  have  propounded  K 

*  It  may  be  observed  tliat  this  distinction  was  not  propounded  by 
Mr.  Wallace— nor,  so  far  as  I  am  aware,  by  anybody  else — until  he 
joined  issue  with  me  on  the  subject  of  specific  characters.  Whether  he 
has  always  held  this  important  distinction  between  specific  and  generic 
characters,  I  know  not ;  but,  as  originally  enunciated,  his  doctrine  of 
utility  as  universal  was  subject  to  no  such  limitation :  it  was  stated 
unconditionally,  as  apjilying  to  all  taxonomic  divisions  indifferently. 
The  words  have  already  been  quoted  on  page  180;  and,  if  the  reader 
will  turn  to  them,  he  may  further  observe  that,  prior  lo  our  discussion, 
Mr.  Wallace  made  no  allowance  for  the  principle  oi  correlation,  which, 


-w^ 


Characters  as  Adaptive  and  Specific.  269 

On  what  then  do  Mr.  Wallace  and  his  followers 
rely  for  their  great  distinction  between  specific  and 
all  other  characters  in  respect  of  utility?  This  is 
the  final  and  fundamental  question  which  I  must 
leave  these  naturalists  themselves  to  answer ;  for  my 
whole  contention  is,  that  it  is  unanswerable.  iUit 
although  I  am  satisfied  that  they  have  nothing  o\\ 
which  to  base  their  generalization,  it  seems  worth 
while  to  conclude  by  showing  yet  one  further  point. 
And  this  is,  that  these  naturalists  themselves,  as  soon 
as  they  quit  merely  abstract  assertions  and  come  to 
deal  with  actual  facts,  contradict  their  own  general- 
ization. It  is  worth  while  to  show  this  by  means  of 
a  few  quotations,  that  we  may  perceive  how  impossible 
it  is  for  them  to  sustain  their  generalization  in  the 
domain  of  fact. 

As  it  is  desirable  to  be  brief,  I  will  confine  myself 
to  quoting  from  Mr.  Wallace. 

"  Colour  may  be  looked  upon  as  a  necessary  result  of  the 
highly  complex  chemical  constitution  of  animal  tissues  and 
fluids.  The  blood,  the  bile,  the  bones,  the  fat,  and  other 
tissues  have  characteristic,  and  often  brilliant  colours,  which 
we  cannot  suppose  to  have  been  determined  for  any  special 
purpose  as  colours,  since  they  are  usually  concealed.  The 
external  organs  and  integuments,  would,  by  the  same  general 
laws,  naturally  give  rise  to  a  greater  variety  of  colour '." 

Surely  comment  is  needless.  Have  the  colour  of 
external  organs  and  integuments  nothing  to  do  with 

as  we  have  seen,  furnishes  so  convenient  a  loop-hole  of  escape  in  cases 
where  even  the  argument  from  our  ignorance  of  possible  utility  appears 
absurd.  In  his  latest  work,  however,  he  is  much  less  sweeping  in 
his  statements.  He  limits  his  doctrine  to  the  case  of  "  specific  charac- 
ters "  alone,  and  even  with  regard  to  them  makes  unlimited  drafts  upon 
the  principle  of  correlation. 
'  Panuinism,  p.  297. 


•*f3" 


>':■■■' 


1,1 


Wi 


270        Danvm,  and  after  Darwin. 

the  determining  of  specific  distinctions  by  system- 
atists?  Or,  may  we  not  rather  ask,  are  there  any 
other  "  characters  "'  which  have  had  more  to  do  with 
their  delineation  of  animal  species  ?  Therefore,  if 
"  the  external  organs  and  integuments  naturally  give 
rise  to  a  greater  variety  of  colours,"  for  non-utilitarian 
reasons,  than  is  the  case  with  internal  organs  and 
tissues ;  while  even  the  latter  present,  for  similarly 
non-utilitarian  reasons,  such  variety  and  intensity  of 
colours  as  they  do ;  must  it  not  follow  that,  on  the 
ground  of  the  "Laws  of  Growth"  alone,  Mr.  Wallace 
has  conceded  the  entire  case  as  regards  "  a  large 
proportional  number  of  specific  characters"  being 
non-adaptive — "spontaneous"  in  their  occurrence, 
and  "  meaningless  "  in  their  persistence  ? 
Once  more : — 

"  The  enormously  lengthened  plumes  of  the  bird  of  paradise 
and  of  the  peacock,  can,  however,  have  no  such  use  [i.e.  for  pur- 
poses of  defence],  but  must  be  rather  injurious  than  beneficial 
in  the  birds'  ordinary  life.  The  fact  that  they  have  been  de- 
veloped to  so  great  an  extent  in  a  few  species  is  an  indication 
of  such  perfect  adaptation  to  the  conditions  of  existence,  such 
complete  success  in  the  battle  for  life,  that  there  is,  in  the 
adult  male  at  all  events,  a  surplus  of  strength,  vitality,  and 
growth-power,  which  is  able  to  expend  itself  in  this  way  without 
injury.  That  such  is  the  case  is  shown  by  the  great  abuii- 
dance  of  most  of  the  species  which  possess  these  wonderful 


superfluities    of    plumage. 


Why,    in    allied    species,   the 


development  of  accessory  plumes  has  taken  different  forms,  we 
are  unable  to  say,  except  that  it  may  be  due  to  that  individual 
variability  which  has  served  as  a  starting-point  for  so  much 
of  what  seems  to  us  strange  in  form,  or  fant.istic  in  colour, 
both  in  the  animal  and  vegetable  world'." 

Here,  again,  one  need  only  ask,  How  can  such  state- 

Darwinism,  pp. -292-3. 


Characters  as  Adaptive  and  Specific.    271 

ments  be  reconciled  with  the  j^rcat  doc^ma,  "  which  is 
indeed  a  necessary  deduction  from  the  theory  of 
Natural  Selection,  namely,  that  none  of  the  definite 
facts  of  organic  nature,  no  special  orj^an.  no  character- 
istic form  or  marking  can  exist,  but  wiiich  must  now 
be.  Of  once  have  been,  useful  '  ?  Can  it  be  said  that 
the  pkimcs  of  a  bird  of  paradise  present  "  no  charac- 
teristic form,"  or  the  tail  of  a  peacock  "  no  character- 
istic marking  "  ?  Can  it  be  held  that  all  the  '•  fantastic 
colours."  which  Darwin  attributes  to  sexual  selection, 
and  all  the  '*  strange  forms  *'  in  the  vegetable  world 
which  present  no  conceivable  reference  to  adai)tation, 
are  to  be  ascribed  to  '•  individual  variability"  without 
reference  to  utility,  while  at  the  same  time  it  is  held, 
"  as  a  necessary  deduction  from  the  theory  of  Natural 
Selection,"  that  all  specific  characters  must  be  •  use- 
ful"  }  Or  must  we  not  conclude  that  we  have  here 
a  contradiction  as  direct  as  a  contradiction  can 
well  be  *  ? 

Nor  is  it  any  more  possible  to  reconcile  these 
contradictory  statements  by  an  indefinite  extension 
of  the  term  *'  correlation,"  than  we  found  it  to  be  in 
the  cases  previously  quoted.  It  might  indeed  be 
logically  possible,  howsoever  biologically  absurd,  to 
attribute  the  tail  of  a  peacock — with  all  its  elabora- 
tion of  structure  and  pattern  of  colour,  with  all  the 
drain  that  its  large  size  and  weight  makes  upon  the 
vital  resources  of  the  bird,  with  all  the  increased 
danger  to  which  it  exposes  the  bird  by  rendering  it 
more  conspicuous,  more  easy  of  capture,  &c. — to 
correlation  with  some   useful   character   peculiar   to 

'  Since  the  above  was  written  both  Mr.  Guliok  and  Professor  Lloyd 
Morgan  have  independently  noticed  the  contradiction. 


*i%^ 


■si 


[I    "  aM 


272         Darwin,  and  after  Darwin. 

peacocks.  But  to  say  that  it  is  due  to  correlation 
with  general  "vitality,"  is  merely  to  discharge  the 
doctrine  of  correlation  of  any  assignable  meaning. 
Vitality,  or  '•  perfect  adaptation  to  the  conditions  of 
existence,"  is  obviously  a  prime  condition  to  the 
occurrence  of  a  peacock's  tail,  as  it  is  to  the  occur- 
rence of  a  peacock  itself;  but  this  is  quite  a  different 
thing  from  saying  that  the  specific  characters  which 
are  presented  by  a  peacock's  tail,  although  useless 
in  themselves,  are  correlated  with  some  other  and 
useful  specific  characters  of  the  same  bird — as  we  saw 
in  a  previous  chapter  with  reference  to  secondary 
sexual  characters  in  general.  Therefore,  when  Mr. 
Wallace  comes  to  the  obvious  question  why  it  is  that 
even  in  "  allied  species,"  which  must  be  in  equally 
"  perfect  adaptation  to  the  conditions  of  existence," 
there  are  no  such  *'  wonderful  superfluities  of  plumage," 
he  falls  back — as  he  previously  fell  back — on  what- 
ever unknown  causes  it  may  have  been  which  pro- 
duced the  peacock's  tail,  when  the  primary  condition 
to  their  operation  has  been  furnished  by  "  complete 
success  in  the  battle  for  life." 

I  have  quoted  the  above  passages,  not  so  much  for 
the  sake  of  exposing  fundamental  inconsistencies  on 
the  part  of  an  adversary,  as  for  the  sake  of  observing 
that  they  constitute  a  much  truer  exposition  of 
"  Darwinism "  than  do  the  contradictory  views  ex- 
pressed in  some  other  parts  of  the  work  bearing  that 
title.  For  even  if  characters  of  so  much  size  and  elabo- 
ration as  the  tail  of  a  peacock,  the  plumes  of  a  bird  of 
paradise  &c.,  are  admitted  to  be  due  to  non-utilitarian 
causes,  much  more  must  innumerable  other  characters 
of  incomparably  less  size  and  elaboration  be  mere 


llil 


Characters  as  Adaptive  ami  Spccijic.   273 

"superfluities."     Without  being  actually  deleterious. 

'•a  large  proportional  number  of  specific  characters," 

who:-e  utility  is  not  apparent,  mw^in  fortiori  \\A^iz  been 

due  to  'individual  variation, '  to  'general  laws  which 

determine  the  production"  of  such  characters     or,  in 

short,  to  some  causes  other   than  natural  selection. 

And  this,  I  say,  is  a  doctrine  much  more  in  harmony 

with  "  Darwinism  "  than  is  the  contradictory  doctrine 

which  I  am  endeavouring  to  resist. 

But   once   again,    and   still    more   generally,    after 

saying  of  '*  the  delicate  tints  of  s[)ring  foliage,  and  the 

intense  hues  of  autumn,"  that  ''as  colours  they  are 

unadaptive,  and  appear  to  have  no  more  relation  to 

the    well-being   of    plants   themselves   than   do   the 

colours  of  gems  and  minerals,"  Mr.  Wallace  proceeds 

thus : — 

"We  may  also  include  in  the  same  cate{:[ory  those  al},'ae 
and  fungi  which  have  bright  colours  -the  red  snow  of  the 
Arctic  regions,  the  red,  green,  or  purple  seaweeds,  the  brilliant 
scarlet,  yellow,  white  or  black  agarics,  and  other  fungi.  All 
these  colours  are  probably  the  direct  results  of  chemical  com- 
position or  moleculai  structure,  and  being  thus  normal  [)roducts 
of  the  vegetable  organism,  need  no  special  explanation  from 
our  present  point  of  view  ;  and  the  same  remark  will  apply 
to  the  varied  tints  of  the  bark  of  trunks,  branches  and  twigs, 
which  are  often  of  various  shades  of  brown  and  green,  or 
even  vivid  reds  and  yellows'." 

Here,  as  Mr.  Gulick  has  already  observed,  "  Mr. 

Wallace  seems  to  admit  that  instead  of  useless  specific 

characters  being  unknown,  they  are  so  common  and 

so  easily  explained  by  *  the  chemical  constitution  of 

the  organism  '  that  they  claim  no  special  attention  ^." 

^  Darwinism,  p.  303. 

^  American  Journal  of  Science,  Vol.  XL.  art.  I.  on  The  Inconsistencits 
of  Utilitarianism  as  the  Excluxive  Theory  of  Organic  Evolution. 

II.  T 


274         Darwin,  and  after  Darwin. 


'%1 


And  whatever  answer  Mr.  Wallace  may  make  to  thi« 
criticism,  I  do  not  sec  how  he  is  to  meet  the  point  at 
present  before  us  namely,  that,  upon  his  own  show- 
ing, there  are  in  nature  numberless  instances  of 
•characters  which  are  useless  without  bcin^  hurtful," 
and  which  nevertheless  present  absolute  '•  constancy." 
If,  in  t)rdcr  to  explain  the  contradiction,  he  should  fall 
back  upon  the  principle  of  correlation,  the  case  would 
not  be  in  any  way  improved.  For,  here  again,  if  the 
term  correlation  were  extended  so  as  to  include  'the 
chemical  constitution  or  the  molecular  structure  of 
the  organism,"  it  would  thereby  be  extended  so  as  to 
discharge  all  Darwinian  significance  from  the  term. 

Summary. 

I  will  conclude  this  discussion  of  the  Utility 
question  by  recapitulating  the  main  points  in  an 
order  somewhat  different  from  that  iu"  which  they 
have  been  presented  in  the  foregoing  chapters  Such 
a  variation  may  render  their  mutual  connexions  more 
apparent.  But  it  is  only  to  the  main  points  that 
allusion  will  here  be  made,  and,  in  order  the  better 
to  show  their  independent  character,  I  will  separately 
number  them. 


PI 


I.  The  doctrine  of  utility  as  universal,  whether 
with  respect  to  species  only  or  likewise  with  respect 
to  specific  characters,  is  confessedly  an  a  priori 
doctrine,  deduced  by  way  of  general  reasoning  from 
the  theory  of  natural  selection. 

a.  Being  thus  founded  exclusively  on  grounds  of 
deduction,  the  doctrine  cannot  be  combated  by  any 


Characters  as  Adaptive  and  Sptrijic.   275 

appeal  to  facts.  For  this  question  is  not  one  of  fact : 
it  is  a  question  of  rcasoninj^.  The  trtalnicnt  of  our 
subject  matter  is  logical  :  not  bif)h)^ical. 

3.  The  doctrine  is  botli  universal  and  absolute. 
Accord in|^  to  one  form  of  it  all  species,  and  accord inj» 
to  anotiicr  form  of  it  all  sj)eciric  cliaracters,  must 
necessarily  be  due  to  the  princii)Ie  of  utility. 

4.  The  doctrine  in  l)olli  its  forms  is  deduced  from 
a  definition  of  the  theory  of  natural  selection  as 
a  theory,  and  the  sole  theory,  of  the  orij^in  of  sf>ecies\ 
but,  as  I'rofes.sor  Huxley  has  already  shown,  it  docs 
not  really  follow,  even  from  this  definition,  that  all 
specific  characters  must  be  '  necessarily  useful.' 
Hence  the  two  forms  of  the  doctrine,  althou^^h  coin- 
cident with  regard  to  species,  are  at  variance  with 
one  another  in  respect  of  specific  characters.  Thus 
far,  of  course,  I  agree  with  Professor  Huxley;  but 
if  I  have  been  successful  in  showing  that  the  above 
definition  of  the  theory  of  natural  selection  is  logically 
fallacious,  it  follows  that  the  doctrine  in  both  its 
form*  is  radically  erroneous.  The  theory  of  natural 
selection  is  not,  accurately  speaking,  a  theory  of  the 
origin  of  species:  it  is  a  theory  of  the  origin  and 
cumulative  development  of  adaptations,  to  whatever 
order  of  taxonomic  division  <-hese  may  happen  to 
belong.  Thus  the  premisses  of  the  deduction  which 
we  are  considering  collapse  :  the  principle  of  utility 
is  shown  not  to  have  any  other  or  further  reference 
to  species,  or  to  specific  characters,  than  it  has  to 
fixed  varieties,  genera,  families,  &c.,  or  to  the  char- 
acters severally  distinctive  of  each 

5.  But,  quitting  all  such  antecedent  considera- 
tions, we  next  proceeded  to  examine  the  doctrine 

T  1 


^ 


276         Darwin^  and  after  Darwin. 


's.... 


¥1 

i 


r  I 


^?  posteriori^  taking  the  arcjuments  which  have  been 
advanced  in  favour  of  the  doctrine,  other  than  those 
which  rest  upon  the  fallacious  definition.  These 
arguments,  as  presented  by  Mr.  Wallace,  are  two  in 
number. 

First,  it  is  represented  that  natural  selection  must 
occupy  the  whole  field,  because  no  other  principle 
of  change  can  be  allowed  to  operate  in  the  presence 
of  natural  selection.  Now  I  fully  agree  that  this 
statement  holds  as  regards  any  principle  of  change 
which  is  deleterious,  but  I  cannot  agree  that  it  does 
so  as  regards  any  such  principle  which  is  merely 
neutral,  No  reason  has  ever  been  shown  why  natural 
selection  should  interfere  with  *'  indifferent"  characters 
—  to  adopt  Professor  Huxley's  term — supposing  such 
to  have  been  produced  by  any  of  the  agencies  which 
we  shaU  presently  have  to  name.  Therefore  this 
argument—  or  rather  assertion — goes  for  nothing. 

Mr.  Wallace's  second  argument  is.  that  utility  is 
the  only  principle  which  can  endow  specific  characters 
with  their  characteristic  stability.  But  this  again 
is  mere  assertion.  Moreover,  it  is  assertion  opposed 
alike  to  common  sense  and  to  observable  fact.  It 
is  opposed  to  common  sense,  because  it  is  obvious 
that  any  other  principle  would  equally  confer  stability 
on  characters  due  to  it,  provided  that  its  action  is 
constant,  as  Darwin  expressly  held.  Again,  this 
argument  is  opposed  to  fact,  because  we  know  of 
thousands  of  cases  where  peculiar  characters  are 
stable,  which,  nevertheless,  cannot  possibly  be  due 
to  natural  selection.  Of  such  are  the  Porto  Santo 
rabbits,  the  niata  cattle,  the  ducks  in  St.  James 
Park,  turkeys,  dogs,  horses,  &c.,  and,  in  the  case  of 


Characters  as  Adaptive  and  Specific.   277 


been 
those 
These 
wo  in 

must 
inciple 
esence 
t  this 
:hange 
t  does 
merely 
latural 
racters 
g  such 

which 
e  this 

'g- 
ility  is 

racters 

again 

pposed 

LCt.      It 

)bvious 

tability 

:tion  is 

n,    this 

now  of 

2rs    are 

be   due 

Santo 

James 

case  of 


plants,  wheat,  cabbage,  maize.  &c.,  as  well  as  all 
the  hosts  of  climatic  varieties,  both  of  animals  and 
plants,  in  a  state  of  nature.  Indeed,  on  taking  a 
wide  survey  of  the  facts,  we  do  not  find  that  the 
principle  of  utility  is  any  better  able  to  confer 
stability  of  character  than  are  many  other  principles, 
both  known  and  unknown.  Nay,  it  is  positively  less 
able  to  do  so  than  are  some  of  these  other  principles. 
Darwin  gives  two  very  probable  reasons  for  this 
fact ;  but  I  need  not  quote  them  a  second  time.  It 
is  enough  to  have  seen  that  this  argument  from 
stability  or  constancy  is  no  less  worthless  thrtii  the 
previous  one.  Yet  these  are  the  only  two  arguments 
of  a  corroborative  kind  which  Mr.  Wallace  adduces 
whereby  to  sustain  his  '"  necessary  deduction." 

6.  At  this  point,  therefore,  it  may  well  seem  that 
we  need  not  have  troubled  ourselves  any  further 
with  a  generalization  which  does  not  appear  to  have 
anything  to  support  it.  And  to  this  view  of  the 
case  I  should  myself  agree,  were  it  not  that  many 
naturalists  now  entertain  the  doctrine  as  an  essential 
article  of  their  Darwinian  creed.  Hence,  I  proceeded 
to  adduce  considerations  per  contra. 

Seeing  that  the  doctrine  in  question  can  only  rest 
on  the  assumption  that  there  is  no  cause  other  than 
natural  selection  which  is  capable  of  originating  any 
single  species — if  not  even  so  much  as  any  single 
specific  character — I  began  by  examining  this  assump- 
tion. It  was  shown  first  that,  on  merely  antecedent 
grounds,  the  assumption  is  "infinitely  precarious." 
There  is  absolutely  no  justification  for  the  state- 
ment that  in  all  the  varied  and  complex  processes  of 
organic  nature  natural  selection  is  the  only  possible 


h 

\P 

P. 


if'' 


lii 


278         Darzvm,  and  after  Darwin. 

cjuse  of  specific  change.  But,  apart  altogether 
from  this  a  priori  refutation  of  the  dogma,  our 
analysis  went  on  to  show  that,  in  point  of  actual 
fact,  there  are  not  a  few  well-known  causes  of  high 
generality,  which,  while  having  no  connexion  with 
the  principle  of  utility,  are  demonstrably  capable 
of  originating  species  and  specific  characters — if  by 
"species"  and  "specific  characters"  we  are  to  under- 
stand organic  types  which  are  ranked  as  species, 
and  characters  which  are  described  as  diagnostic 
of  species.  Such  causes  I  grouped  under  five  dif- 
ferent headings,  viz.  Climate^  Food,  Sexual  Selection, 
Isolation,  and  Laws  of  Growth.  Sexual  Selection 
and  Isolation  are,  indeed,  repudiated  by  Mr.  Wallace  ; 
but,  in  common  I  believe  with  all  biologists,  he 
accepts  the  other  three  groups  of  causes  as  fully 
adequate  to  produce  such  kinds  and  decrees  of 
modification  as  are  taken  to  constitute  specific  dis- 
tinction. And  this  is  amply  sufficient  for  our  present 
purposes.  Besides,  under  the  head  of  Sexual  Selection, 
it  does  not  signify  in  the  present  connexion  whether 
or  not  we  accept  Darwin's  theory  on  this  subject. 
For,  in  any  case,  the  facts  of  secondary  sexual  char- 
acters are  indisputable:  the?e  characters  are,  for  the 
most  part,  specific  characters:  and  they  cannot  he 
explained  by  the  principle  of  utility.  E.en  Mr. 
Wallace  does  not  attempt  to  do  so ;  and  the  ex- 
planation which  he  does  give  is  clearly  incompatible 
with  his  doctrine  touching  the  necessarily  life-serving 
value  of  all  specific  characters.  Lastly,  the  same  lias 
to  be  said  of  the  Laws  of  Growth.  For  we  have  just 
seen  that  on  the  grounds  of  this  principle  likewise 
Mr.  Wallace  abandons  the  doctrine  in  question.     As 


Characters  as  Adaptive  and  Specific.  279 


high 


regards  Isolation,  much  more  remains  to  be  said  in 
the  ensuing  portion  of  this  work,  while,  as  regards 
Climatic  Variation,  there  are  literally  innumerable 
cases  where  changes  of  specific  type  are  known  to 
have  been  caused  by  this  means. 

7.  To  the  latter  class  of  cases,  however,  it  will  be 
objected  that  these  changes  of  specific  type,  although 
no  doubt  sufficiently  '*  stable  "  so  long  as  the  changed 
conditions  remain  constant,  are  found  by  experiment 
not  to  be  hereditary ;  and  this  clearly  makes  all  the 
difference  between  a  true  specific  change  and  a  merely 
fictitious  appearance  of  it. 

Well,  in  the  first  place,  this  objection  can  have 
reference  only  to  the  first  two  of  the  five  principles 
above  stated.  It  can  have  no  reference  to  the  last 
three,  because  of  these  heredity  constitutes  the  very 
foundation.  This  consideration  ought  to  be  borne  in 
mind  throughout.  But  now.  in  the  second  place,  even 
as  regards  changes  produced  by  climate  and  food,  the 
reply  is  nugatory.  And  this  for  three  reasons,  as 
follows. 

(a)  No  one  is  thus  far  entitled  to  conclude  agfainst 
the  possible  transmission  of  acquired  characters;  and, 
so  long  as  there  is  even  so  much  as  a  possibility  of 
cHmatic  (or  any  other  admittedly  non-utilitarian) 
variations  becoming  in  this  way  hereditary,  the  reply 
before  us  merely  begs  the  question. 

(b)  Even  supposing,  for  the  sa'e  of  argument,  that 
acquired  characters  can  never  in  any  case  become 
congenital,  there  remains  the  strong  probability — 
sanctioned  as  such  even  by  Wcismann — that  changed 
conditions  of  life  may  not  unfrequently  act  upon  the 
material  of  heredity  itself,  th 


givn 


specific 


^m 


•si 


Mi 


280         Darwt'n,  and  after  Darwin. 

changes  which  are  from  the  first  congenital,  though 
not  utilitarian.  Indeed,  there  are  not  a  few  facts 
(Hoffmann's  plants,  Weismann's  butterflies,  &c.), 
which  can  only  be  explained  either  in  this  way,  or 
as  above  {a).  And  in  the  present  connexion  it  is 
immaterial  which  of  these  alternative  explanations 
we  choose  to  adopt,  seeing  that  they  equally 
refute  our  opponents'  objection.  And  not  only 
do  these  considerations— («)  and  {b) — refute  this 
particular  objection  ;  they  overturn  on  new  and 
independent  grounds  the  whole  of  our  opponents' 
generalization.  For  the  generalization  is,  that  the 
principle  of  utility,  acting  through  natural  selection, 
is  "  necessarily "  the  sole  principle  which  can  be 
concerned  in  hereditary  changes  of  specific  type. 
But  here  we  perceive  both  a  possibility  {a)  and  a 
probability  {b),  if  not  indeed  a  certainty,  that  quite 
other  principles  have  been  largely  concerned  in  the 
production  of  such  changes. 

(c)  Altogether  apart  from  these  considerations, 
there  remains  a  niurh  more  important  one.  For 
the  objection  that  fixed  —  or  "stable" — climatic 
varieties  differ  from  true  species  in  not  being  sub- 
ject to  heredity,  raises  the  question — What  are  we 
to  understand  by  a  "  species".^  This  question,  which 
was  thus  far  purposely  left  in  abeyance,  had  now 
to  be  dealt  with  seriously.  For  it  would  clearly 
be  irrational  in  our  opponents  to  make  this  highly 
important  generalization  with  regard  to  species  and 
specific  characters,  unless  they  are  prepared  to  tell 
us  what  they  mean  by  species,  and  therefore  by 
characters  as  specific.  In  as  far  as  there  is  any 
ambiguity  on  this  point  it    makes  entirely   for  our 


Characters  as  Adaptive  and  Specific.  281 

side  in  the  debate,  because  even  any  small  degree 
of  uncertainty  with  regard  to  it  would  render  the 
generalization  in  question  proportionally  unsound. 
Yet  it  is  notorious  that  no  word  in  existence  is  more 
vague,  or  more  impossible  to  define,  than  the  word 
"species."  The  very  same  men  who  at  one  time 
pronounce  their  great  generalization  with  regard  to 
species,  at  another  time  asseverate  that  "a  species 
is  not  a  definite  entity/'  but  a  merely  abstract  term, 
serving  to  denote  this  that  and  the  other  organic  type, 
which  this  that  and  the  other  systcmatist  regards 
as  deserving  such  a  title,  Moreover  it  is  acknow- 
ledged that  systematists  differ  among  themselves 
to  a  wide  extent  as  to  the  kinds  and  degrees  of 
peculiarity  which  entitle  a  given  form  to  a  specific 
rank.  Even  in  the  same  department  of  systematic 
work  much  depends  on  merely  individual  taste,  while 
in  different  departments  widely  different  standards 
of  delimination  are  in  vogue.  Hence,  our  reductio 
ad  absurdiwi  consists  in  this — that  whether  a  given 
form  is  to  be  regarded  as  necessarily  due  to  natural 
selection,  and  whether  all  its  distinctive  characters 
are  to  be  regarded  as  necessarily  utilitarian  characters, 
will  often  depend  on  whether  it  has  been  described  by 
naturalist  A  or  by  naturalist  B.  There  is  no  one 
criterion — there  is  not  even  any  one  set  of  criteria — 
agreed  upon  by  naturalists  for  the  construction  of 
specific  types.  In  particular,  as  regards  the  principle 
of  heredity,  it  is  not  known  of  one  named  species 
in  twenty — probably  not  in  a  hundred — whether  its 
diagnostic  characters  are  hered'tary  characters  ;  while, 
on  the  other  hand,  even  in  cases  where  experiment 
has  proved  "  constant  varieties  "  to  be  hereditary — 


^^f^ 


ill 


h: 


f 


282         Dafwin,  and  after  Darwin. 

and  even  also  cross-sterile  with  allied  varieties — it  is 
only  some  three  or  four  living  botanists  who  for  these 
reasons  advocate  the  elevation  of  such  varieties  to 
the  rank  of  species.  In  short,  as  we  are  not  engaged  on 
any  abstract  question  touching  the  principles  on  which 
species  ought  to  have  been  constituted  by  their  makers, 
but  upon  the  actual  manner  in  which  they  have  been, 
the  criterion  of  heredity  must  needs  be  disregarded  in 
the  present  discussion,  as  it  has  been  in  the  work  of 
systematists.  And  the  result  of  this  is,  that  any 
objection  to  our  introducing  the  facts  of  climatic  varia- 
tion in  the  present  discussion  is  excluded.  In  par- 
ticular, so  far  as  any  question  of  heredity  is  concerned, 
all  these  facts  are  as  assuredly  as  they  are  cogently 
relevant.  It  is  perfectly  certain  that  there  is  "  a  large 
proportional  number  "  of  named  species — particularly 
of  plants — which  further  investigation  would  resolve 
into  climatic  varieties.  With  the  advance  of  know- 
ledge, "  bad  species"  are  always  increasing  at  the 
expense  of  "good  species,"  so  that  we  are  now  justified 
in  concluding  with  Kerner.  Hackel,  and  other  naturalists 
best  qualified  to  speak  on  this  subject,  that  if  we  could 
know  as  much  about  the  past  history  and  present  rela- 
tions of  the  remaining  good  species  as  we  do  about  the 
bad,  all  the  former,  without  exception,  would  become 
resolved  into  the  latter.  In  point  of  fact,  and  apart 
altogether  from  the  inductive  experience  on  which  this 
conclusion  is  based,  the  conclusion  follows  "  as  a  neces- 
sary deduction  "  from  the  general  theory  of  descent. 
For  this  theory  essentially  consists  in  supposing 
either  the  past  or  the  present  existence  of  interme- 
diate varietal  forms  in  all  cases,  with  the  consequence 
that  "  good  species  "  serve  merely  to  mark  lacunae  in 


III 


Characters  as  Adaptive  and  Specific.  283 

our  knowledge  of  what  is  everywhere  a  finely  gradu- 
ated process  of  transmutation.  Hence,  if  we  place 
this  unquestionably  ''  necessary  deduction "  from 
the  general  theory  of  descent  side  by  side  with  the 
alleged  "  necessary  deduction "  from  the  theory  of 
natural  selection,  we  cannot  avoid  the  following 
absurdity — Whether  or  not  a  given  form  is  to  be 
regarded  as  necessarily  due  to  natural  selection, 
and  all  its  characters  necessarily  utilitarian,  is  to  be 
determined,  and  determined  solely,  by  the  mere 
accident  of  our  having  found,  or  not  having  found, 
either  in  a  living  or  in  a  fossil  state,  its  varietal 
ancestry. 

8.  But  this  leads  us  to  consider  the  final  and 
crowning  incongruities  which  have  been  dealt  with  in 
the  present  chapter.  For  here  we  have  seen,  not 
only  that  our  opponents  thus  draw  a  hard  and  fast 
line  between  "varieties"  and  'species"  in  regard 
to  "  necessary  origin  "  and  '*  necessary  utility,"  but  that 
they  further  draw  a  similar  line  between  "  species " 
and  '*  genera "  in  the  same  respects.  Yet,  in  ac- 
cordance with  the  general  theory  of  evolution,  it  is 
plainly  as  impossible  to  draw  any  such  line  in  the 
one  case  as  it  is  to  do  so  in  the  other.  Just  as 
fixed  varieties  are  what  Darwin  called  "  incipient 
species,"  so  are  species  incipient  genera,  genera 
incipient  faniilies,  and  so  on.  Evolutionists  must 
believe  that  the  process  of  evolution  is  everywhere 
the  same.  Nevertheless,  while  admitting  all  this,  the 
school  of  Huxley  contradicts  itself  by  alleging  some 
unintelligible  exception  in  the  case  of  "  species,"  while 
the  school  of  Wallace  presses  this  exception  so  as  to 
embrace  "  specific  characters."     Indeed  Mr.  Wallace, 


t!      Ml 


A 


284         Darwiyif  and  after  Darwin, 


^ 


:) 


h 

IS. 


♦1 


IN,,, 


3 


S'! 


("I 


> 


It     I 


IM; 


Mi 


while  maintaining  that  all  specific  characters  must 
necessarily  be  useful,  maintains  at  the  same  time 
that  any  number  of  varietal  characters  on  the  one 
hand,  and  a  good  half  of  generic  characters  on 
the  other,  are  probably  useless.  Thus  he  contra- 
dicts his  argument  from  the  *'  constancy  of  specific 
characters"  (seeing  that  generic  characters  are  still 
more  constant),  as  later  on  we  saw  that  he  contra- 
dicts his  deductive  generalization  touching  their 
necessary  utility,  by  giving  a  non-utilitarian  ex- 
planation of  whole  multitudes  of  specific  characters. 
I  need  not,  however,  again  go  over  the  ground  so 
recently  traversed  ;  but  will  conclude  by  once  more 
recurring  to  the  only  explanation  which  I  have 
been  able  to  devise  of  the  otherwise  inexplicable 
fact,  that  in  regard  to  this  subject  so  many  natural- 
ists still  continue  to  entangle  themselves  in  the 
meshes  of  absurdity  and  contradiction. 

The  only  conceivable  explanation  is,  that  these 
naturalists  have  not  yet  wholly  divested  themselves 
of  the  special  creation  theory.  Although  professing 
to  have  discarded  the  belief  that  "species"  are 
"definite  entities,"  differing  in  kind  from  "varieties" 
on  the  one  hand  and  from  "genera"  on  the  other, 
these  writers  are  still  imbued  with  a  vague  survival 
of  that  belief.  They  well  know  it  to  belong  to  the 
very  essence  of  their  new  theory  that  "species" 
are  but  "  pronounced  varieties,"  or,  should  we  prefer 
it,  "  incipient  genera " ;  but  still  they  cannot  alto- 
gether escape  the  pre-Darwinian  conception  of  species 
as  organic  units,  whose  single  mode  of  origin  need 
not  extend   to  other   taxonomic   groups,  and  whose 


Characters  as  Adaptive  and  Specific.  285 

characters  therefore  present  some  exceptional  si'frnifi- 
cance  to  the  scientific  naturalist.  So  to  speak,  such 
divinity  doth  still  hedge  a  species,  that  even  in  the 
very  act  of  declaring  it  but  an  idol  of  their  own 
creation,  these  naturali.sts  bow  before  their  fetish  as 
something  that  is  unique — differing  alike  in  its  origin 
and  in  its  characters  froi  the  varieties  beneath  and 
the  genera  above.  The  consequence  is  that  they 
have  endeavoured  to  reconcile  these  incompatible 
ideas  by  substituting  the  principle  of  natural  selec- 
tion for  that  of  super-natural  creation,  where  the 
particular  case  of  "species"  is  concerned  In  this 
way,  it  vaguely  seems  to  them,  they  are  able  to 
save  the  doctrine  of  some  one  mode  of  origin  as 
appertaining  to  species,  which  need  not  "necessarily" 
appertain  to  any  other  taxonomic  division.  All 
other  such  divisions  they  regard,  with  their  pre- 
Darwinian  forefathers,  as  merely  artificial  construc- 
tions ;  but,  likewise  with  these  forefathers,  they  look 
upon  species  as  natural  divisions,  proved  to  be  such 
by  a  single  and  necessary  mode  of  origin.  Hence, 
Mr.  Wallace  expressly  defines  a  species  with  reference 
to  this  single  and  necessary  mode  of  origin  {see  above, 
p.  235),  although  he  must  be  well  aware  that  there  Is 
no  better,  or  more  frequent,  proof  of  it  in  the  case 
of  species,  than  there  is  in  that  of  soniewhat  less 
pronounced  types  on  the  one  hand  (fixed  varieties), 
or  of  more  pronounced  types  on  the  other  (genera, 
families,  &c.).  Hence,  also,  the  theory  of  natural 
selection  is  defined  as  par  excellence  a  theory  of  the 
origin  of  species ;  it  is  taken  as  applying  to  the 
particular  case  of  the  origin  of  species  in  a  peculiarly 
stringent  manner,  or   in   a  manner  which   does   not 


i 

I 


286         Darwin,  and  after  Darwin. 


1    > 
J  '"t 

\    * 


1 


K 


apply  to  the  orit;in  of  any  other  groups.  And 
I  believe  that  an  important  accessory  reason  of  the 
continuance  of  this  view  for  more  than  thirty  years 
after  the  publication  of  the  Origin  of  Species  by  meatis 
of  Natural  Selection,  is  to  be  found  in  the  title  of  that 
work.  "  Natural  Selection  "  has  thus  become  verbally 
associated  with  "  Origin  of  Species,"  till  it  is  thought- 
lessly felt  that,  in  some  way  or  another,  natural  selec- 
tion must  have  a  peculiar  reference  to  those  artificially 
delineated  forms  which  stand  anywhere  between 
a  fixed  variety  and  a  so-called  genus.  This  verbal 
association  has  no  doubt  had  the  effect  of  still  further 
preserving  the  traditional  halo  of  mystery  which  clings 
to  the  idea  of  a  *'  species."  Hence  it  comes  that  the 
title  which  Darwin  chose — and,  looking  to  the  circum- 
stances of  the  time,  wisely  chose — for  his  great  work, 
has  subsequently  had  the  effect  of  fostering  the  very 
idea  which  it  was  the  object  of  that  work  to  dissipate, 
namely,  that  species  are  peculiar  entities,  which  differ 
more  or  less  in  origin  or  kind  from  all  other  taxonomic 
groups.  The  full  title  of  this  work  \s,~The  Origin  of 
Species  by  means  of  Natural  Selection:  or  the  Preserva- 
tion of  Favoured  Races  in  the  Struggle  for  Life.  Now, 
supposing  that  instead  of  this  its  author  had  chosen 
some  such  title  as  the  following: — The  Origin  of 
Organic  Types  by  means  of  Adaptive  Evolution :  or 
Survival  of  the  Fittest  Forms  in  the  Struggle  for  Life. 
Of  course  this  would  have  been  a  bad  substitute  from 
various  points  of  view ;  but  could  any  objection  have 
been  urged  against  it  from  our  present  point  of  view  ? 
I  do  not  see  that  there  could.  Yet,  if  such  had  been 
the  title,  I  have  little  doubt  that  we  should  never  have 
heard  of  those  great  generalizations  with  regard  to 


i 


Characters  as  Adaptive  and  Sf^ccific.    287 

species  and  specific  characters,  the  futility  of  which  it 
has  been  the  object  of  ihcse  cliapters  to  expose. 

In  conclusion,  it  only  remains  to  reiterate  that  in 
thus  combating  what  appears  to  me  plainly  errone- 
ous deductions  from  the  theory  of  natural  selection, 
I  am  in  no  wise  combating  that  theory  itself.  On 
the  contrary,  I  hope  that  I  am  rendering  it  no  unim- 
portant service  ay  endeavouring  to  relieve  it  of 
a  parasitic  growth — an  accretion  of  false  loi^ic 
Regarding  as  I  do  the  theory  of  natural  selecti(Mi  as, 
primarily,  a  theory  of  the  origin  (or  cumulative 
development)  of  adaptations,  I  see  in  merely  non- 
adaptive  characters — be  they  "specific"  or  other — 
a  comparatively  insignificant  class  of  phenomena. 
which  may  be  due  to  a  great  variety  of  incidental 
causes,  without  any  further  reference  to  the  master- 
principle  of  natural  selection  than  that  in  the  presence 
of  this  principle  none  of  these  non-adaptive  characters 
can  be  actively  deleterious.  But  that  there  may  be 
"any  number  of  indiftcrent  characters"*  it  is  no  part 
of  the  theory  of  natural  selection  to  deny ;  and  all 
attempts  to  foist  upon  it  apriori  "  deductions  "  opposed 
alike  to  the  facts  of  nature  and  to  the  loc^ic  of 
the  case,  can  only  act  to  the  detriment  of  the  great 
generalization  which  was  expressly  guarded  from  such 
fallacies  by  the  ever-careful  judgement  of  Darwin. 


: 

j 

; 

1 

^ 

K 


•,"•» 


li:^ 


APPENDICES  AND  NOTES 


n. 


'S 


'♦l 


I: 


H 


m 


'-#«! 

N 


APPENDIX  I. 


On  Panmixia. 

There  are  several  points  of  considerable  theoretical  im- 
portance connected  with  Panmixia,  which  were  omitted 
from  the  text,  in  order  to  avoid  distracting  attention  from 
the  main  issue  which  is  there  under  consideration.  These 
side  issues  may  now  be  appropriately  presented  in  the  form 
in  which  they  were  published  in  Nature,  March  13,  1890'. 
After  stating,  in  almost  the  same  words,  what  has  already 
been  said  in  Chapter  X,  this  paper  proceeds,  with  the  excep- 
tion of  a  few  verbal  alterations,  as  follows. 

"There  is,  however,  one  respect  in  which  Professor  Weismann's 
statement  of  the  principle  of  panmixia  differs  from  that  which  was 
considered  by  Mr.  Darwin  ;  and  it  is  this  difference  of  statement 
— which  amounts  to  an  important  difference  of  theory  —that  I 
now  wish  to  discuss. 

"  The  difference  in  question  is,  that  while  Professor  Weismann 
believes  the  cessation  of  selection  to  be  capable  of  inducing  de- 
generation down  to  the  almost  complete  disappearance  of  a  rudi- 
mentary organ,  I  have  argued  that,  u?tless  assisted  by  some  other 
principle,  it  can  at  most  only  reduce  the  degenerating  or^an  to 
considerably  above  one-half  its  original  size  —or  probably  not 
through  so  much  as  one-quarter.  The  ground  of  this  argument 
(which  is  given  in  detail  in  the  Nature  articles  of  1873-1874)  is, 
that  panmixia  depends  for  its  action  upon  fortuitous  variations 
round  an  ever-iliminishing  average— the  average  thus  diminish- 
ing because  it  is  no  longer  sustained  by  natural  selection.  But 
although  no  longer  sustained  by  natural  selection,  it  does  con- 

^  Vol.  xh.  p.  438. 
U  a 


^^ 


*«., 


»«4 


292         Darwm,  and  after  Darwin. 

tinue  to  be  sustained  by  heredity,  and  therefore,  as  long  as  the 
force  of  heredity  persists  unimpaired,  fortuitous  variations  alone — 
or  variation  which  is  no  longer  controlled  by  natural  selection — 
cannot  reduce  the  dwindling  organ  to  so  much  as  one-half  of 
its  original  size ;  indeed,  as  above  foreshadowed,  the  balance 
between  the  positive  force  of  heredity  and  the  negative  effects 
of  promiscuous  variability  will  most  likely  be  arrived  at  above 
the  middle  line  thus  indicated.  Only  if  for  any  reason  the 
force  of  heredity  begins  to  fail  can  the  average  round  which  the 
cessation  of  selection  works  become  a  progressively  diminishing 
average.  In  other  words,  so  long  as  the  original  force  of  heredity 
as  regards  the  useless  organ  remains  unimpaired,  the  mere  with- 
drawal of  selection  cannot  reduce  the  organ  much  below  the  level 
of  eCciency  above  which  it  was  previously  maintained  by  the 
presence  of  selection.  If  we  take  this  level  to  be  80  or  90  per 
cent,  of  the  original  size,  cessation  of  selection  will  reduce  the 
organ  through  the  10  or  20  per  cent.,  and  there  leave  it  fluc- 
tuating about  this  average,  unless  for  any  reason  the  force  of 
heredity  begins  to  fail— in  which  case,  of  course,  the  average  will 
progressively  fall  in  proportion  to  the  progressive  weakening 
of  this  force. 

"  Now,  according  to  my  views,  the  force  of  heredity  under  such 
circumstances  is  always  bound  to  fail,  and  this  for  two  reasons. 
In  the  first  place,  it  must  usually  happen  that  when  an  organ 
becomes  useless,  natural  selection  as  regards  that  organ  will  not 
only  cease,  but  become  reversed.  For  the  organ  is  now  absorbing 
nutriment,  causing  weight,  occupying  space,  and  so  on,  uselessly. 
Hence,  even  if  it  be  not  also  a  source  of  actual  danger,  'economy 
of  growth '  will  determine  a  reversal  of  selection  against  an  organ 
which  is  now  not  merely  useless,  but  deleterious.  And  this  de- 
generating influence  of  the  reversal  of  selection  will  throughout  be 
assisted  by  the  cessation  of  selection,  which  will  now  be  always 
acting  round  a  continuously  sinking  average.  Nevertheless, 
a  point  of  balance  will  eventually  be  reached  in  this  case,  just  as 
it  was  in  the  previous  case  where  the  cessation  of  selection  was 
supposed  to  be  working  alone.  For,  where  the  reversal  of  selec- 
tion has  reduced  the  diminishing  organ  to  so  minute  a  size  that 
its  presence  is  no  longer  a  source  of  detriment  to  the  organism, 
the  cessation  of  selection  will  carry  the  reduction  a  small  degree 


Appendix  I. 


293 


as  the 

alone — 
ction— 
■half  of 
balance 
!  effects 
t  above 
5on  the 
lich  the 
inishing 
leredity 
re  with- 
he  level 
i  by  the 
■  90  per 
luce  the 
i  it  flue- 
force  of 
rage  will 
■akening 

der  such 
reasons. 
,n  organ 
iwill  not 
bsorbing 
uselessly. 
economy 
an  organ 
this  de- 
ighout  be 
e  always 
jrtheless, 
;e,  just  as 
ction  was 
of  selec- 
size  that 
)rganism, 
ill  degree 


further;  and  then  the  organ  will  remain  as  a  'rudiment.'  And 
so  it  will  remain  permanently,  unless  there  be  some  further  reason 
why  the  still  remaining  force  of  heredity  should  be  abolished. 
This  further  (or  second)  reason  I  found  in  the  consideration  that, 
however  enduring  we  may  suppose  the  force  of  heredity  to  be,  we 
cannot  suppose  that  it  is  actually  everlasting  ;  and,  therefore, 
that  we  may  reasonably  attribute  the  eventual  disappearance  of 
rudimentary  organs  to  the  eventual  failure  of  heredity  itself.  In 
support  of  this  view  there  is  the  fact  that  rudimentary  organs, 
although  very  persistent,  are  not  everlasting.  That  they  should 
be  very  persistent  is  what  we  should  expect,  if  the  hold  which 
heredity  has  upon  them  is  great  in  proportion  to  the  time  during 
which  they  were  originally  useful,  and  thus  firmly  stamped  upon 
the  organization  by  natural  selection  causing  them  to  be  strongly 
inherited  in  the  first  instance.  For  example,  we  might  expect 
that  it  would  be  more  ditficuit  finally  to  eradicate  the  rudiment  of 
a  wing  than  the  rudiment  of  a  feather  ;  and  accordingly  we  find 
it  a  general  rule  that  long-enduring  rudiments  are  rudiments  of 
organs  distinctive  of  the  higher  taxonomic  divisions —i.e.  of 
organs  which  were  longest  in  building  up,  and  therefore  longest 
sustained  in  a  state  of  working  efficiency. 

"  Thus,  upon  the  whole,  my  view  of  the  facts  of  degeneration 
remains  the  same  as  it  was  when  first  published  in  these  columns 
seventeen  years  ago,  and  may  be  summarized  as  follows. 

"  The  cessation  of  selection  when  working  alone  (as  it  probably 
does  during  the  first  centuries  of  its  action  upon  structures 
or  colours  which  do  not  entail  any  danger  to,  or  perceptible  drain 
upon,  the  nutritive  resources  of  the  organism)  cannot  cause  de- 
generation below,  probably,  some  10  to  20  per  cent.  But  if  from 
the  first  the  cessation  of  selection  has  been  assisted  by  the 
reversal  of  selection  (on  account  of  the  degenerating  structure 
having  originally  been  of  a  size  sutllci-^nt  to  entail  a  perceptible 
drain  on  the  nutritive  resources  of  the  organism,  having  now 
become  a  source  of  danger,  and  so  forth^,  the  two  principles 
acting  together  will  continue  to  reduce  the  ever-diminishing 
structure  down  to  the  point  at  which  its  presence  is  no  longer 
a  perceptible  disadvantage  to  the  species.  When  that  point  is 
reached,  the  reversal  of  selection  will  terminate,  and  the  cessation 
of  selection  will  not  then  be  able  of  itself  to  reduce  the  organ 


294         Darwin f  and  after  Darwin, 


K 


If;*'* 


hi 


\ 


through  more  than  at  most  a  very  few  further  percentages  of  its 
original  size.  But,  after  this  point  has  been  reached,  the  now 
total  absence  of  selection,  either  for  or  against  the  organ,  will 
sooner  or  later  email  this  further  and  most  important  consequence, 
a  failure  of  heredity  as  regards  the  organ.  So  long  as  the 
organ  was  of  use,  its  efficiency  was  constantly  maintained  by 
the /r(?j^«^^  of  selection — which  is  merely  another  way  of  saying 
that  selection  was  constantly  aiaintaining  the  force  of  heredity  as 
regards  that  organ.  But  as  soon  as  the  organ  ceased  to  be  of 
use,  selection  ceased  to  maintain  the  force  of  heredity;  and  thus, 
sooner  or  later,  that  force  began  to  waver  or  fade.  Now  it  is 
this  wavering  or  fading  of  the  force  of  heredity,  thus  originally 
due  to  the  cessation  of  selection,  that  in  turn  co-operates  with 
the  still  continued  cessation  of  selection  in  reducing  the  structure 
below  the  level  where  its  reduction  was  left  by  the  actual  reversal 
of  selection.  So  that  from  that  level  downwards  the  cessation 
of  selection,  and  the  consequent  failing  of  heredity,  act  and  react 
in  their  common  work  of  causing  obsolescence.  In  the  case  of 
newly  added  characters,  the  force  of  heredity  will  be  less  than 
in  that  of  more  anciently  added  characters ;  and  thus  we  can 
understand  the  long  endurance  of  *  vestiges '  characteristic 
of  the  higher  taxonomic  divisions,  as  compared  with  those 
characteristic  of  the  lower.  But  in  all  cases,  if  time  enough  be 
allowed  under  the  cessation  of  selection,  the  force  of  heredity 
will  eventually  fall  to  zero,  when  the  hitherto  obsolescent  structure 
will  finally  become  obsolete.  In  cases  of  newly  added  and 
comparatively  trivial  characters,  with  regard  to  which  reversal 
of  selection  is  not  likely  to  take  place  (e.g.  slight  differences  of 
colour  between  allied  species),  cessation  of  selection  is  likely  to 
be  very  soon  assisted  by  a  failure  in  the  force  of  heredity ;  seeing 
that  such  newly  added  characters  will  not  be  so  strongly 
inherited  as  are  the  more  ancient  characters  distinctive  of  higher 
taxonomic  groups. 

"  Let  us  now  turn  to  Weismann's  view  of  degeneration.  First 
of  all,  he  has  omitted  to  perceive  that  *  panmixia '  alone  (if  un- 
assisted either  by  reversed  selection  or  an  inherent  diminishing 
of  the  force  of  herediv/j  cannot  reduce  a  functionless  organ 
to  the  condition  of  a  rudiment.  Therefore  he  everywhere 
represents  panmixia  (or  the  mere  cessation  of  selection)  as  of 


Appendix  I. 


295 


itself  sufficient  to  cause  degeneration,  say  from  \oo  to  5,  instead 
of  from  100  to  90  or  80,  which,  for  the  reasons  above  given, 
appeared  (and  still  appears)  to  me  about  the  most  that  this 
principle  can  accomplish,  so  long  as  tlie  original  force  of  heredity 
continues  unimpaired.  No  doubt  a'c  have  here  what  must  be 
regarded  as  a  mere  oversight  on  the  part  of  Professor  Weis- 
mann ;  but  the  oversi;_;ht  is  rendered  remarkable  by  the  fact 
that  he  does  invoke  the  aid  of  reversed  selection  /'«  or(fer  to 
explain  the  final  disappearance  of  a  rudivient.  Yet  it  is  self- 
evident  that  the  reversal  of  selection  muse  be  much  more  active 
during  the  initial  than  during  the  final  sta,<:^es  of  degeneration, 
seeing  that,  ex  hypothesis  the  greater  the  degree  of  reduction 
which  has  been  attained  the  less  must  be  the  detriment  arising 
from  any  useless  expenditure  of  nutrition,  &c. 

"  And  this  leads  me  to  a  secimd  oversight  in  Professor  Weis- 
mann's  statement,  which  is  of  more  importance  than  the  first. 
For  the  place  at  which  he  does  invoke  the  assistance  of  reversed 
selection  is  exactly  the  place  at  which  reversed  selection  must 
necessarily  have  ceased  to  act.  This  place,  as  already  ex- 
plained, is  where  an  obsolescent  organ  has  become  rudimentary, 
or,  as  above  supposed,  reduced  to  5  per  cent,  of  its  original  size ; 
and  the  reason  why  he  invokes  the  aid  of  reversed  selection  at 
this  place  is  in  order  to  save  his  doctrine  of  *  the  stability  of 
germ-plasm.'  That  the  force  of  heredity  should  finally  become 
exhausted  if  no  longer  maintained  by  ih^  presence  of  selection, 
is  what  Darwin's  theory  of  perishable  gemmules  would  lead 
us  to  expect,  while  such  a  fact  would  be  fatal  to  Weismann's 
theory  of  an  imperishable  germ-plasm.  Therefore  he  seeks  to 
explain  the  eventual  failure  of  heredity  (which  is  certainly  a  fact) 
by  supposing  that  after  the  point  at  which  the  cessation  of  selec- 
tion alone  can  no  longer  act  (and  which  his  first  oversight  has 
placed  some  80  per  cent,  too  low),  the  reversal  of  selection  will 
begin  to  act  directly  against  the  force  of  heredity  as  regards  the 
diminishing  organ,  until  such  direct  action  of  reversed  selection 
will  have  removed  the  organ  altogether.  Or,  in  his  own  words, 
'The  complete  disappearance  of  a  rudimentary  organ  can  only 
take  place  by  the  operation  of  natural  selection ;  this  principle 
will  lead  to  its  diminution,  inasmuch  as  the  disappearing  struc- 
ture takes  the  place  and  the  nutriment  of  other  useful  and  im- 


Hi 


i:    t 


296         Darwm^  and  after  Darwin. 


1: 


''3 


k: 


'^1 


portant  organs.'  That  is  to  say,  the  rudimentary  organ  finally 
disappears,  not  because  the  force  of  heredity  is  finally  exhausted, 
but  because  natural  selection  has  begun  to  utilize  this  force 
against  the  continuance  of  the  organ — always  picking  out  those 
congenital  variations  of  the  organ  which  are  of  smallest  size,  and 
thus,  by  its  now  reversed  action,  reversing  the  I'orce  of  heredity 
as  regards  the  organ. 

**  Now  the  oversight  here  is  in  not  perceiving  that  the  smaller 
the  disappearing  structure  becomes,  the  less  hold  must  'this 
principle'  of  reversed  selection  retain  upon  it.  As  above 
observed,  during  the  earlier  stages  of  reduction  (or  while  co- 
operating with  the  cessation  of  selection)  the  reversal  of  selec- 
tion will  be  at  its  maximum  of  efficiency  ;  and,  as  the  process 
of  diminution  continues,  a  point  must  eventually  be  reached  at 
which  the  reversal  of  selection  can  no  longer  act.  Take  the 
original  mass  of  a  now  obsolescent  organ  in  relation  to  that 
of  the  entire  organism  of  which  it  then  formed  a  part  to  be 
represented  by  the  ratio  i  :  100.  For  the  sake  of  argument  we 
may  assume  that  the  mass  of  the  organism  has  throughout 
remained  constant,  and  that  by  *  mass '  in  both  cases  is  meant 
capacity  for  absorbing  nutriment,  causing  weight,  occupying 
space,  and  so  forth.  Now,  we  may  further  assume  that  when 
the  mass  of  the  organ  stood  to  that  of  its  organism  in  the  ratio 
of  1 :  100,  natural  selection  was  strongly  reversed  with  respect 
to  the  organ.  But  when  this  ratio  fell  to  i  :  loco,  the  activity  of 
such  reversal  must  have  become  enormously  diminished,  even 
if  it  still  continued  to  exercise  any  influence  at  all.  For  we  must 
remember,  on  the  one  hand,  that  the  reversal  of  selection  can 
only  act  as  long  as  the  presence  of  a  diminishing  organ  con- 
tinues to  be  so  injurious  that  variations  in  its  size  are  matters  of 
life  and  death  in  the  struggle  for  existence ;  and,  on  the  other 
hand,  that  natural  selection  in  the  case  of  the  diminishing  organ 
does  not  have  reference  to  the  presence  and  the  absence  of  the 
organ,  but  only  to  such  variations  in  its  mass  as  any  given 
generation  may  supply.  Now,  the  process  of  reduction  does 
not  end  even  at  i  :  1000.  It  goes  on  to  i :  10,000,  and  eventually 
I  :  oe.  Consequently,  however  great  our  faith  in  natural  selec- 
tion may  be,  a  point  must  eventually  come  for  all  of  us  at  which 
we  can  no  longer  believe  that  the  reduction  of  an  obsolescent 


11 


J!     I 


I  finally 

lausted, 
is  force 
at  those 
ize,  and 
leredity 

smaller 
ist  'this 
5  above 
hile  co- 
jf  selec- 
process 
ached  at 
'ake  the 
to  that 
rt  to  be 
ment  we 
roughout 
s  meant 
:cupying 
lat  when 
the  ratio 
1  respect 
ctivity  of 
ed,  even 
we  must 
:tion  can 
^an  con- 
latters  of 
he  other 
ng  organ 
ce  of  the 
ny  given 
ion  does 
ventually 
ral  selec- 
at  which 
solescent 


Appendix  I, 


297 


organ  is  due  to  reversed  selection.  And  I  cannot  doubt  that  if 
Professor  Weismann  had  sufHciently  considered  the  matter,  he 
would  not  have  committed  himself  to  the  statement  that  'the 
complete  disappearance  of  a  rudimentary  organ  can  only  twke 
place  by  the  operation  of  natural  selection.' 

"  According  to  my  view,  the  complete  disappearance  of  a  rudi- 
mentary ori(un  can  only  take  place  by  the  cessation  of  natural 
selection,  which  permits  the  eventual  exhaustion  of  heredity, 
when  heredity  is  thus  simply  left  to  itself.  During  all  the  earlier 
stages  of  reduction,  the  cessation  of  selection  was  assisted  in  its 
work  by  the  reversal  of  selection ;  but  when  the  rudiment 
became  too  small  for  such  assistance  any  longer  to  be  supplied, 
the  rudiment  persisted  in  that  greatly  reduced  condition  until 
the  force  of  heredity  with  regard  to  it  was  eventually  worn 
out.  This  appears  to  me,  as  it  appeared  in  1873,  the  only 
reasonable  conclusion  that  can  be  drawn  from  the  facts.  And 
it  is  because  this  conclusion  is  fatal  to  Professor  Weismann's 
doctrine  of  the  permanent  '  stability '  of  germ-plasm,  while 
quite  in  accordance  with  all  theories  which  belong  to  the  family 
of  pangenesis,  that  I  deem  the  facts  of  degeneration  of  great 
importance  as  tests  between  these  rival  interpretations  of  the 
facts  of  heredity.  It  is  on  this  account  that  I  have  occupied  so 
much  space  with  the  foregoing  discussion;  and  i  shall  be  glad 
to  ascertain  whether  any  of  the  followers  of  Professor  W  eismann 
are  able  to  controvert  these  views. 

"  George  J.  Romanes." 

"  r.S. — Since  the  above  article  was  sent  in,  Professor  Weismann 
has  published  in  these  columns  (February  6)  his  reply  to  a  criti- 
cism by  Professor  Vines  (October  24,  1889).  In  this  reply 
he  appears  to  have  considerably  modified  his  views  on  the 
theory  of  degeneration ;  tor  while  in  his  Essays  he  says  (as  in 
the  passage  above  quoted)  that  '  the  complete  disappearance  of 
a  rudimentary  organ  can  only  take  place  by  the  operation 
of  natural  selection' — i.e.  only  by  the  reversal  of  selection,— in 
his  reply  to  Professor  Vines  he  says,  '  I  believe  that  I  have 
proved  that  organs  no  longer  in  use  become  rudimentary,  and 
must  finally  disappear,  solely  by  "panmixia";  not  through  the 
direct  action  of  disuse,  but  because  natural  selection  no  longer 


v.. 


!    ! 

i   ) 

';■   I" 


1%      l\ 


1 


[•if. 

III  '"^ 

fo 

Ik  "* 


298         Dafwin,  and  after  Darwin. 

sustains  their  standard  structure' — i.e.  solely  by  the  cessation 
of  selection.  Obviously,  there  is  here  a  flat  contradiction.  It 
Professor  Weismann  now  believes  that  a  rudimentary  organ 
'must  finally  disai)pear  solely^  through  the  withdrawal  of 
selection,  he  has  abandoned  his  previous  belief  that  'the 
complete  disappearance  of  a  rudimentary  organ  can  only  take 
place  by  the  operation  of  selection. '  And  this  change  of  belief 
on  his  part  is  a  matter  of  the  highest  importance  to  his  system 
of  theories  as  a  whole,  since  it  betokens  a  surrender  of  his 
doctrine  of  the  'stability'  of  germ-plasm  -  or  of  the  virtually 
everlasting  persistence  of  the  force  of  heredity,  and  the 
consequent  necessity  for  a  reversal  of  this  force  itself  (by  natural 
selection  placing  its  premium  on  minus  instead  of  on  plus 
variations),  in  order  that  a  rudimentary  organ  should  finally 
disappear.  In  o'lher  words,  it  now  seems  he  no  longer  believes 
that  the  force  of  heredity  in  one  direction  (that  of  sustaining 
a  rudimentary  organ)  can  only  be  abolished  by  the  active  influence 
of  natural  selection  determining  this  force  in  the  opposite 
direction  (that  of  removing  a  rudimentary  organ).  It  seems  he 
now  believes  that  the  force  of  heredity,  if  merely  left  to  itself 
by  the  withdrawal  of  natural  selection  altogether,  will  sooner  or 
later  become  exhausted  through  the  mere  lapse  of  time.  This, 
of  course,  is  my  own  theory  of  the  matter  as  originally  published 
in  these  columns ;  but  I  do  not  see  how  it  is  to  be  reconciled 
with  Professor  Weismann's  doctrine  of  so  high  a  degree  of 
stability  on  the  part  of  germ-plasm,  that  we  must  look  to  the 
Protozoa  and  the  Protophyta  for  the  original  source  of  congenital 
variations  as  now  exhibited  by  the  Metazoa  and  Metaphyta. 
Nevertheless,  and  so  far  as  the  philosophy  of  degeneration  is 
concerned,  I  shall  be  very  glad  if  (as  it  now  appears)  Professor 
Weismann's  more  recent  contemplation  has  brought  his  principle 
of  panmixia  into  exact  coincidence  with  that  of  my  cessation 
of  selection." 

Before  passing  on  it  may  here  be  noted  that,  to  any  one 
who  believes  in  the  inheritance  of  acquired  characters,  there 
is  open  yet  another  hypothetical  cause  of  degeneration,  and 
one  to  which  the  final  disappearance  of  vestigial  organs  may 
be  attributed.     Roux  has  shown  in  his  work  on  Tlie  Struggle 


ifl 


r 


Appendix  I, 


299 


for  Existence  between  Parts  0/ an  Organism  that  the  principle 
of  selection  must  operate  in  every  constituent  tissue,  and  as 
between  every  coni-tituent  cell  of  wiiich  an  organism  is  com- 
posed. Now,  if  an  organ  falls  into  disuse,  its  constituent  cells 
become  worsted  in  their  struggles  with  other  cells  in  the 
organism.  Hence,  degeneration  of  the  disused  organ  may 
progressively  increase,  quite  ipdependenlly  of  any  struggle 
for  existence  on  the  part  of  the,  organism  as  a  whole.  Con- 
sequently, regeneration  may  proceed  without  any  reference 
to  the  princii)le  of  *'  economized  nutrition  "  ;  and,  if  it  does 
so,  and  if  the  effects  of  its  doing  so  are  transmitted  from 
generation  to  generation,  the  disused  org.m  will  finally  dis- 
appear by  means  of  Roux's  principle. 

The  long  communication  above  quoted  led  to  a  still  longer 
correspondence  in  the  pages  of  Nature.  For  Professor  Ray 
Lankester  wrote'  to  imjtugn  the  doctrine  of  panmixia, or  cessa- 
tion of  selection,  in  toto,  arguing  with  much  insistence  that 
"cessation  of  selection  must  be  supplemented  by  economy  of 
growth  in  onier  to  produce  the  results  attributed  to  panmixia." 
In  other  words,  he  denied  that  panmixia  alone  can  cause 
degeneration  in  any  degree  at  all :  at  most,  he  said,  it  can 
be  but  "  a  condition,"  or  "  a  state,"  which  occurs  when  an 
organ  or  part  ceases  to  be  useful,  and  iheiefore  falls  under 
the  degenerating  influence  of  active  causes,  such  as  economy 
of  nutrition.  Or,  in  yet  other  words,  he  refused  to  recognize 
that  any  degenerative  process  can  be  due  to  natural  selection 
as  merely  withdrawn :  only  when,  besides  being  withdrawn, 
n'citural  selection  is  reversed^  did  he  regard  a  degenerative 
process  as  possible.  As  a  result  of  the  correspondence, 
however,  he  eventually  ^  agreed  that,  if  th--  "  birth-mean  "  of 
an  organ,  in  respect  either  of  size  or  complexity  of  structure, 
be  lower  than  the  "  selection-mean"  while  the  organ  is  useful 
(a  fact  which  he  does  not  dispute) ;  then,  if  the  organ  ceases 


'  Nature,  vol.  xli.  p.  486. 


'  Ibid.  vol.  xlii.  p.  53. 


■«l 


300         Darwin^  and  after  Darwin, 


1 


no 

k  < 


to  be  useful,  it  will  degenerate  by  tlie  withdrawal  of  selection 
alone.  Wiiich,  of  course,  is  merely  a  re-statement  of  the 
doctrine  of  panmixia,  or  cessation  of  selection,  in  somewhat 
varied  terminology — provided  that  the  birth-mean  be  taken 
over  a  number  of  generations,  or  not  only  over  a  few  follow- 
ing the  selection-mean  of  the  structure  while  still  in  its 
highest  stale  of  efficiency.  For  the  sake  of  brevity  I  will 
hereafter  speak  of  these  "  few  following  "  generations  by  the 
term  of  "  first  generations." 

It  remains  to  consiiler  the  views  of  Professor  Lloyd 
Morgan  upon  the  subject.  In  my  opinion  he  is  the 
shrewdest,  as  well  as  the  most  logical  critic  that  we  have 
in  the  field  of  Darwinian  speculation;  therefore,  if  possible, 
I  should  like  to  arrive  at  a  full  agreement  with  him  upon 
this  matter.  His  latest  utterance  witii  regard  to  it  is  as 
follows : — 

"To  account  for  the  diminution  of  organs  or  structures 
no  longer  oi  use,  apart  from  any  inherited  effects  of  disuse, 
Mr.  Romanes  has  invoked  the  Cessation  of  Selection;  and 
Mr.  Francis  (lalton  has,  in  another  connexion,  summarized  the 
effects  of  this  cessation  of  selection  in  the  convenient  phrase 
*  Regression  to  Mediocrity.'  This  is  the  Panmixia  of  P'^jfessor 
W'eismann  and  his  followers ;  but  the  phrase  regression  to 
mediocrity  through  the  cessation  of  selection  appears  to  me 
preferable.  It  is  clear  that  so  long  as  any  organ  or  structure 
is  subject  to  natural  selection  through  elimination,  it  is,  if  not 
actually  undergoing  improvement,  kept  at  a  high  standard  of 
cflficiency  through  the  elimination  of  all  those  individuals  in 
which  the  organ  in  question  falls  below  the  required  standard. 
But  if,  from  change  in  the  environment  or  any  other  cause,  the 
character  in  question  ceases  to  be  subject  to  selection,  elimina- 
tion no  longer  takes  place,  and  the  high  standard  will  no  longer 
be  maintained.  There  will  be  reversion  to  mediocrity.  The 
probable  amount  of  this  reversion  is  at  present  a  matter  under 
discussion '." 


Presidential  Address  to  the  Bristol  Naturalists'  Society,  1891. 


lection 
of  the 

newhat 
taken 

follow- 
in  its 
I  will 
by  the 

Lloyd 
is  the 
re  have 
ossible, 
n  upon 
it  is  as 

ructures 
disuse, 
and 
ized  the 
phrase 
jfessor 
sion   to 
to  me 
tructure 
if  not 
idard  of 
duals  in 
landard. 
e,  the 
elimina- 
0  longer 
The 
kr  under 


1891. 


Appendix  1. 


301 


So  far,  then,  Professor  Lloyd  Morgan  is  in  complete 
agreement  with  previous  writers  upon  the  subject.  He  does 
not  doubt  that  the  cessation  of  selection  must  always  be 
a  cause  of  degeneration  :  the  only  question  is  as  to  the 
potency  of  this  cause,  or  the  amount  of  degeneration  which 
it  is  callable  of  effecting. 

Taking,  first,  the  case  of  bulk  or  size  of  an  organ,  as 
distinguished  from  its  organization  or  complexity,  we  have 
seen  that  VVeismann  represents  the  cessation  of  selection — 
even  if  working  quiie  alone,  or  without  any  assistance  from 
the  reversal  of  selection — to  be  capable  of  reducing  a  fully 
developed  organ  to  the  state  of  a  rudiment,  or  even,  if  we 
take  his  most  recent  view,  of  abolishing  the  organ  in  toto. 

Professor  Lloyd  Morgan,  on  the  other  hand,  does  not 
think  that  the  cessation  of  selection  alone  can  cause  reduc- 
tion further  than  the  level  of  "  mediocrity "  in  the  first 
generations — or,  which  is  much  the  same  thing,  further  than 
the  difference  between  the  "  birth-moan  "  and  the  "  seUc  on- 
mean  "  of  the  first  generations.  This  amount  of  reduction 
he  puts  at  5  per  cent.,  as  "  a  very  liberal  estimate." 

Here,  then,  we  have  three  estimates  of  the  amount  of 
degeneration  which  c;in  be  produced  by  panmixia  alone, 
where  mere  size  or  bulk  of  an  organ  is  concerned — say, 
3  to  5  per  cent.,  10  to  20  per  cent.,  and  95  per  cent,  to  o. 
At  first  sight,  these  differences  appear  simply  ludicrous ; 
but  on  seeking  for  the  reasons  of  them,  we  find  that  they 
are  due  to  different  views  touching  the  manner  in  which 
panmixia  operates.  The  oversights  which  have  led  to 
Weismann's  extremely  high  estimate  have  already  been 
stated.  The  reason  of  the  difference  between  the  extremely 
low  estimate  of  Professor  Lloyd  Morgan,  as  compared  with 
my  own  intermediate  one,  is,  that  lie  supposes  the  power 
of  panmixia  to  become  exhausted  as  soon  as  the  level  of 
mediocrity  of  the  first  generations  has  become  the  general 
level  in  succeeding  generations.     In  my  view,  however,  the 


. 

\ 

302         DarwiHf  and  after  Darwin. 


I 


K  5 


level  of  mediocrity  is  itself  a  sinking  level  in  successive 
generations,  with  the  result  that  there  is  no  reason  why  the 
reducing  power  of  panmixia  should  ever  become  exhausted, 
save  that  the  more  reduction  it  effects  the  greater  is  the 
force  of  heredity  which  remains  to  be  overcome,  as 
previously  explained.  Thus  the  only  question  between 
Professor  Lloyd  Morgan  and  myself  is — Does  the  level  of 
mediocrity  fall  in  successive  generations  under  the  cessation 
of  selection,  or  does  it  remain  permanently  where  it  used  to 
be  under  the  presence  of  selection  ?  Does  the  "  birth-mean  " 
remain  constant  throughout  any  number  of  generations, 
notwithstanding  that  the  sustaining  influence  of  selection 
has  been  withdrawn ;  or  does  it  progressively  sink  as  a  con- 
sequence of  such  witlidrawal? 

In  order  to  answer  this  question  we  had  better  begin  by 
considering  now  the  case  of  organization  of  structure,  as 
distinguished  from  mere  size  of  structure.  Take  any  case 
where  a  complex  organ — such  as  a  compound  eye — has  been 
slowly  elaborated  by  natural  selection,  and  is  it  not  self- 
evident  that,  when  natural  selection  is  withdrawn,  the  com- 
plex structure  will  deteriorate  ?  In  other  w  ords,  the  level  of 
mediocrity,  say  in  the  hundred  thousandth  generation  after 
the  sustaining  influence  of  natural  selection  has  been  with- 
drawn, will  not  be  so  high  as  it  was  in  the  first  generations. 
For,  by  hypothesis,  there  is  now  no  longer  any  elimination 
of  unfavourable  variations,  which  may  therefore  perpetuate 
themselves  as  regards  any  of  the  parts  of  this  highly  complex 
mechanism  ;  so  that  it  is  only  a  matter  of  time  when  the 
mechanism  must  become  disintegrated.  I  can  scarcely 
suppose  that  any  one  who  considers  the  subject  will  question 
this  statement,  and  therefore  I  will  not  say  anything  that 
might  be  said  in  the  way  of  substantiating  it.  But,  if  the 
statement  be  assented  to,  it  follows  that  there  is  no  need  to 
look  for  any  cause  of  deterioration,  further  than  the  with- 
drawal of  selection — or  cessation  of  the  principle  which  (as 


Appendix  I, 


303 


we  are  supposing)  had  hitlurto  been  the  sole  means  of 
mainuiining  efficient  harmony  amonj?  all  the  intk'penilently 
variable  parts  of  the  lii;,'hly  complex  stniclure. 

Now,  1  hold  that  .he  same  thing  is  true,  though  in  a  lesser 
degree,  as  regards  degeneration  of  size.  Thai  thure  is  no 
difference  in  kind  between  the  two  cases,  Profesbor  Lloyd 
Morgan  inipliciily  allows;  for  what  he  says  is — 

"In  any  long-established  character,  such  as  wing  power  in 
birds,  brain-clevelopmcnt,  the  eyes  of  crustacca,  &c.,  no  short- 
comer  in  these  respects  would  have  been  permitted  by  natural 
selection  to  transmit  his  shortcomings  for  hundreds  of  genera- 
tions. All  tendency  to  such  shortcomings  would,  one  would 
suppose,  have  been  bred  out  of  the  race.  If  after  this  K^ng 
process  of  selection  there  still  remains  a  strong  tendency  to 
deterioration,  this  tendency  demands  an  explanation '." 

Here,  then,  deterioration  as  to  size  of  structure  (wings  of 
birds),  and  deterioration  as  to  complexity  of  structure  (brain 
and  eyes)  are  expressly  put  upon  the  same  fooling.  There- 
fore, if  in  the  latter  case  the  "  tendency  to  deterioration  " 
does  not  "  demand  an  explanation,"  beyond  the  fiicL  that  the 
hitherto  maintaining  influence  has  been  withdrawn,  neither 
is  any  such  furihcr  explanation  demanded  in  the  former  case. 
Which  is  exactly  my  own  view  of  the  matter.  It  is  also 
Mr.  Gallon's  view.  For  although,  in  the  passage  formerly 
quoted,  Professor  Lloyd  Morgan  appears  to  think  that  by  the 
jihrase  "  Regression  to  Mediocrity "  Mr.  Gallon  means  to 
indicate  that  panmixia  can  cause  degeneration  only  as  far  as 
the  mediocrity  level  of  the  first  generations,  this,  in  poit.l  of 
fact,  is  not  what  Gallon  means,  nor  is  it  what  he  says.  The 
phrase  in  question  occurs  "  in  another  connexion,"  and, 
indeed,  in  a  different  puiilication.  Bui  where  he  expressly 
alludes  to  the  cessation  of  selection,  this  is  what  he  says. 
The  italics  are  mine. 

•   Presidential  Address  to  the  Bristol  Naturalists'  Society,  1891. 


304         Darwifiy  and  after  Darwin. 


;i 


I; 

1 


i;;  9 
|f.*« 

.      "1* 

[I  1 


% 


\. 


i 


^t-* 
N 


Mil 


I 


-Si 


"A  special  cauce  may  be  assigned  for  the  effects  of  use  in 
causing  hereditary  atrcphy  of  disused  parts.  It  has  already 
been  ohown  that  all  exceptionally  developed  organs  tend  to  de- 
teriorate :  consequently,  those  that  are  not  protected  by  selec- 
tion will  dwindle.  The  level  of  muscular  efficiency  in  the  wing 
of  a  strongly  flying  bird  [curiously  enough,  the  same  case  that 
is  chosen  by  Professor  Lloyd  Morgan  to  illustrate  his  opposite 
view],  is  like  the  level  of  water  in  the  leaky  vessel  of  a  Danaid, 
only  secured  to  the  race  by  constant  effort,  so  to  speak.  Let 
the  effort  be  relaxed  ever  so  little^  and  the  level  immediately 
falls  *." 

I  take  it,  then,  that  the  burden  of  proof  lies  with  Professor 
Lloyd  Morgan  to  show  why  the  withdrawal  of  selection  is 
not  sufficient  to  account  for  degeneration  any  further  than 
the  mediocrity-level  in  the  former  presence  of  selection. 
Why  does  "  the  strong  tendency  '^  to  deterioration  demand 
an  explanation,"  further  thin  the  fact  that  when  all  variations 
below  the  average  in  every  generation  are  allowed  to  survive, 
they  must  gradually  lower  the  average  itself  through  a  series 
of  generations  ?  To  answer  that  any  such  tendency  "  would 
have  been  bred  out  of  the  race "  by  the  previous  action  of 
selection,  is  to  suppose  that  the  function  of  selection  is  at  an 
end  when  once  it  has  built  up  a  structure  to  the  highest 
point  of  working  efficiency, — that  the  presence  of  selection 
is  no  longer  required  to  maintain  the  structure  at  that  point. 
But  it  is  enough  to  ask  in  reply — Why,  under  the  cessation 
of  selection,  does  complexity  of  structure  degenerate  so 
much  more  rapidly  than  size  of  structure  ?  Why  is  it,  for 
instance,  that  "the  eyes  of  Crustacea"  in  dark  caves  have 
entirely  disappeared,  while  their  foot-stalks  (when  originally 
present)  still  remain?  Can  it  be  maintained  that  "  for 
hundreds  of  generations "  natural  selection  was  more  intent 

*  A  Theory  of  Heredity,  Journal  of  Anthropological  Institute,  1875. 
Vol.  V.  p.  346. 

"^  No  one  has  supposed  that  the  tendency  need  be  "strong":  it  has 
only  to  be  persistent. 


Appendix  I, 


305 


on  developing  the  foot-stalks  than  the  eyes  which  were 
mounted  upon  them — so  that  while  the  latter  were  left  by 
selection  with  "  a  strong  tendency  to  deterioration,"  the 
former  have  had  this  tendency  "  bred  out  in  the  race  "  *  ? 

To  sum  up.  There  is  now  no  question  in  any  quarter 
touching  the  fact  that  panmixia,  or  the  cessation  of  selection, 
is  a  true  cause  of  degeneration.  The  only  question  is  as  to 
the  amount  of  degeneration  which  it  is  able  to  effect  when 
not  assisted  by  the  reversal  of  selection,  or  any  other 
cause  of  degeneration.     Moreover,  even  with  regard  to  this 

*  Of  course  it  must  be  observed  that  degeneration  of  complexity 
involves  also  degeneration  of  size,  so  that  a  more  correct  statement 
of  the  case  would  be — Why,  under  the  cessation  of  selection,  does  an 
organ  of  extreme  complexity  degenerate  much  more  rapidly  than  one  of 
much  less  complexity?  For  example,  under  domestication  the  brains 
of  rabbits  and  ducks  appear  to  have  been  reduced  in  some  cases  by 
as  much  as  50  per  cent.  (Darwin,  and  Sir  J.  Crichton  Browne.)  But 
if  it  is  possible  to  attribute  this  effect — or  part  of  it — to  an  artificial 
selection  of  stupid  animals,  I  give  in  the  text  an  example  occurring 
under  nature.  Many  other  cases,  however,  might  be  given  to  show  the 
general  rule,  that  under  cessation  of  selection  complexity  of  structure 
degenerates  more  rapidly — and  also  more  thoroughly — than  size  of  it. 
This,  of  course,  is  what  Mr.  Galton  and  I  should  expect,  seeing  that  the 
more  complex  a  structure  the  greater  are  the  number  of  points  for 
deterioration  to  invade  when  the  structure  is  no  longer  "protected  by 
selection."  (On  the  other  hand,  of  course,  this  fact  is  opposed  to  the 
view  that  degeneration  of  useless  structures  below  the  "birth-mean"  of 
the  first  generations,  is  exclusively  due  to  the  reversal  of  selection  ;  for 
economy  of  growth,  deleterious  effect  of  weight,  and  so  forth,  ought  to 
affect  size  of  structure  much  more  than  complexity  of  it.)  But  I  choose 
the  above  case,  partly  because  Professor  Lloyd  Morgan  has  himself 
alluded  to  "  the  eyes  of  Crustacea,"  and  partly  because  Professor  Ray 
Lankester  has  maintained  that  the  loss  of  these  eyes  in  dark  caves  is  due 
to  the  reversal  of  selection,  as  distinguished  from  the  cessation  of  it.  In 
view  of  the  above  parenthesis  it  will  be  seen  that  the  point  is  not  of 
much  importance  in  the  present  connexion  ;  but  it  appears  to  me  that 
cessation  of  selection  must  here  have  had  at  least  the  larger  share  in  the 
process  of  atrophy.  For  while  the  economy  of  nutrition  ought  to  have 
removed  the  relatively  \&\gt  foot-sialks  -3  rapidly  as  the  eyes,  I  cannot 
see  that  there  is  any  advantage,  other  than  the  economy  ot  nutrition,  to 
be  gained  by  the  rapid  loss  ol  hard-coated  eyes,  even  though  they  have 
ceased  to  be  of  use. 

II.  X 


iit 


3o6         Darwifif  and  after  Darwin. 


h 


''H. 


It 


}^3 


question  of  amount,  there  is  no  doubt  on  any  side  that 
panmixia  alone  causes  degeneration  more  rapidly  where  it 
has  to  do  with  complexity  of  organization,  than  it  does  where 
it  is  concerned  with  a  mere  reduction  of  mass. 

The  question  as  to  the  amount  of  degeneration  that  is 
caused  by  the  cessation  of  selection  alone  is  without  any 
practical  importance  where  species  in  a  state  of  nacure  are 
concerned,  because  here  the  cessation  of  selection  is  probably 
always  associated  more  or  less  with  the  reversal  of  it ;  and  it 
is  as  impossible  as  it  is  immaterial  to  determine  the  relative 
shares  which  these  two  co-operating  principles  take  in 
bringing  about  the  observed  results.  But  where  organisms 
in  a  state  of  domestication  are  concerned,  the  importance  of 
the  question  before  us  is  very  great.  For  if  the  cessation  of 
selection  alone  is  capable  of  reducing  an  organ  through 
lo  or  12  per  cent,  of  its  original  size,  nearly  all  the  direct 
evidence  on  which  Darwin  relied  in  favour  of  use-inheritance 
is  destroyed.  On  the  other  hand,  if  reduction  through  5  per 
cent,  be  deemed  a  "  very  liberal  estimate "  of  what  this 
principle  can  accomplish,  the  whole  body  of  Darwin's  direct 
evidence  remains  as  he  left  it.  I  have  now  given  my  reasons 
for  rejecting  this  lower  estimate  on  the  one  hand,  and  what 
seems  to  me  the  extravagant  estimate  of  Weismann  on  the 
other.  But  my  own  intermediate  estimate  is  enough  to 
destroy  the  apparent  proof  of  use-inheritance  that  was  given 
by  Darwin.  Therefore  it  remains  for  those  who  deny 
Lamarckian  principles,  either  to  accept  some  such  estimate, 
or  else  to  acknowledge  the  incompatibility  of  any  lower  one 
with  the  opinion  that  there  is  no  evidence  in  favour  of  these 
principles. 


Ill 
f  i' 


ide  that 
vhere  it 
!S  where 


that  is 

out  any 

,i:ure  are 

)robably 

;  and  it 

relative 

take   in 

•ganisms 

•tance  of 

sation  of 

through 
le  direct 
[leritance 
gh  5  per 
I'hat  this 
I's  direct 
r  reasons 
ind  what 
n  on  the 
lough  to 
/as  given 

10  deny 
estimate, 
Dwer  one 

of  these 


APPENDIX   II. 

On  Characters  as  Adaptive  and  Specific. 

It  is  the  object  of  this  Appendix  to  state,  more  fully  than 
in  the  text,  the  opinions  with  regard  to  this  subject  which 
have  been  published  by  the  two  highest  authorities  on  the 
theory  of  natural  selection — Darwin  and  Professor  Huxley. 
I  will  take  first  the  opinion  of  Professor  Huxley,  quoted  in 
extensOy  and  then  consider  it  somewhat  more  carefully  than 
seemed  necessary  in  the  text. 

As  far  as  I  am  aware,  the  only  occasion  on  which 
Professor  Huxley  has  alluded  to  the  subject  in  question,  is  in 
his  obituary  notice  of  Darwin  in  the  Proceedings  of  the  Royal 
Society,  Vol.  XLIV.  No.  269,  p.  xviii.  The  allusion  is  to  my 
paper  on  Physiological  Selection,  in  the  Journal  of  the 
LinncBan  Society,  Zool.  Vol.  XIX,  pp.  337-41 1.  But  it  will  be 
observed  that  the  criticism  has  no  reference  to  the  theory 
which  it  is  the  object  of  that  paper  to  set  forth.  It  refers 
only  to  my  definition  of  the  theory  of  natural  selection  as 
primarily  a  theory  of  the  origin,  or  cumulative  development, 
of  adaptations.  This  criticism,  together  with  my  answer 
thereto  at  the  time,  is  conveyed  in  the  following  words. 

"Every  variety  which  is  selected  into  a  species  is  favoured 
and  preserved  in  consequence  of  being,  in  some  one  or  more 
respects,  better  adapted  to  its  surroundings  than  its  rivals. 
In  other  words,  every  species  which  exists,  exists  in  virtue 
of  adaptation,  and  whatever  accounts  for  that  adaptation  ac- 
counts for  the  existence  of  the  species.    To  say  that  Darwin 

X   2 


m 


w 


p 

IK";) 

I. ;' 


I 


308        Darwin,  and  after  Darwin. 

has  put  forward  a  theory  of  the  adaptation  of  species,  but  not  of 
their  origin,  is  therefore  to  misunderstand  the  first  principles 
of  the  theory.  For,  as  has  been  pointed  out,  it  is  a  necessary 
consequence  of  the  theory  of  selection  that  every  species 
must  have  some  one  or  more  structural  or  functional  pecu- 
liarities, in  virtue  of  the  advantage  conferred  by  which  it  has 
fought  through  the  crowd  of  its  competitors,  and  achieved  a 
certain  duration.  In  this  sense,  it  is  true  that  every  species 
has  been  'originated'  by  selection." 

Now,  in  the  first  place,  I  have  nowhere  said  that  "Darwin 
has  put  forward  a  theory  of  the  adaptation  of  species,  but  not 
of  their  origin."  I  said,  and  continue  to  say,  that  he  has 
put  forward  a  theory  of  adaptations  in  general y  and  th&t 
where  such  adaptations  appertain  to  species  only  (i.e.  are 
peculiar  to  particular  species),  the  theory  becomes  "also  a 
theory  of  the  origin  of  the  species  which  present  them."  The 
only  possible  misunderstanding,  therefore,  which  can  here  be 
alleged  against  me  is,  that  I  fail  to  perceive  it  as  a  "  necessary 
consequence  of  the  theory  of  selection  that  every  species  must 
have  some  one  or  more  structural  or  functional  peculiarities " 
of  an  adaptive  or  utilitarian  kind.  Now,  if  this  is  a  misunder- 
standing, I  must  confess  to  not  having  had  it  removed  by 
Mr.  Huxley's  exposition. 

The  whole  criticism  is  tersely  conveyed  in  the  form  of  two 
sequent  propositions — namely,  "Every  species  which  exists, 
exists  in  virtue  of  adaptation ;  and  whatever  accounts  for  that 
adaptation  accounts  for  the  existence  of  the  species."  My 
answer  is  likewise  two-fold.  First,  I  do  not  accept  the  premiss  ; 
and  next,  even  if  I  did,  I  can  shov;  that  the  resulting  con- 
clusion would  not  overturn  my  defmition.  Let  us  consider 
these  two  points  separately,  beginning  with  the  latter,  as  the 
one  which  may  be  most  briefly  disposed  of. 

I.  Provisionally  conceding  that  "every  species  which  exists, 
exists  in  virtue  of  adaptation,"  I  maintain  that  my  definition 
of  the  theory  of  natural  selection  still  holds  good.  For  even 
on  the  basis  of  this  concession,  or  on  the  ground  of  this 
assumption,  the  theory  of  natural  selection  is  not  shown  to  be 
" primarily  "  a  theory  of  the  origin  of  species.  It  follows,  indeed, 
from  the  assumption — is,  in  fact,  part  and  parcel  ot  the  as- 


Appendix  II. 


309 


sumption— that  all  species  have  been  originated  by  natural 
selection ;  but  why  ?  Only  becattse  natural  selection  has  origin- 
ated those  particular  adaptive  features  in  virtue  of  which  {by  the 
hypothesis)  species  exist  as  species.  It  is  only  in  virtue  of  having 
created  these  features  that  natural  selection  has  created  the 
species  presenting  them — ^just  as  it  has  created  genera,  families, 
orders,  &c.,  in  virtue  of  other  adaptive  features  extending  through 
progressively  wider  areas  of  taxonomic  division.  Everywhere 
and  equally  this  principle  >as  been  "  primarily  "  engaged  in  the 
evolution  of  adaptations,  and  if  one  result  of  its  work  has 
been  that  of  enabling  the  systematist  to  trace  lines  of  genetic 
descent  under  his  divisions  of  species,  genera,  and  the  rest, 
such  a  result  is  but  "  secondary "  or  "  incidental." 

In  short,  it  is  ^^ primarily*'  a  theory  of  adaptations  wher- 
ever these  occur ^  and  only  becomes  ^^ also*'  or  *^ incidentally*' 
a  theory  of  species  in  cases  where  adaptations  happen  to  be 
restricted  in  their  occurrence  to  organic  types  of  a  certain  order 
of  taxonomic  division. 

II.  Hitherto,  for  the  sake  of  argument,  I  have  conceded 
that,  in  the  words  of  my  critic,  "  it  is  a  necessary  consequence 
of  the  theory  of  selection  that  every  species  must  have  some 
one  or  more  structural  or  functional  peculiarities"  of  an 
adaptive  kind.  But  now  I  will  endeavour  to  show  that  this 
statement  does  not  *'  follow  as  a  necessary  consequence " 
from  "the  theory  of  selection." 

Most  obviously  "  it  follows  "  from  the  theory  of  selection  that 
"  every  variety  which  is  selected  into  a  species  is  favoured  and 
preserved  in  consequence  of  being,  in  some  one  or  more 
respects,  better  adapted  to  its  surroundings  than  its  rivals." 
This,  in  fact,  is  no  more  than  a  re-statement  of  the  theory 
itself.  But  it  does  not  follow  that  "  every  species  which  exists, 
exists  in  virtue  of  adaptation"  peculiar  to  that  species;  i.e. 
that  every  species  which  exists,  exists  in  virtue  of  having 
ieen  ^^ selected''  This  may  or  may  not  be  true  as  a  matter 
of  fact :  as  a  matter  of  logic,  the  inference  is  not  deducible 
from  the  selection  theory.  Every  variety  which  is  ^'^  selected 
into"  a  species  must,  indeed,  present  some  such  peculiar 
advantage  ;  but  this  is  by  no  means  equivalent  to  saying,  "in 
other  words,"  that    every  variety  which    becomes    a  species 


3IO        Darwin,  and  after  Darwin. 


'•I 


must  do  so.  For  the  latter  statement  imports  a  completely 
new  assumption — namely,  that  every  variety  which  becomes 
a  species  must  do  so  because  it  has  been  "  selected  into  "  a 
sr«cies.  In  short,  what  we  are  hers  told  is,  that  if  we  believe 
the  selection  principle  to  have  given  origin  to  some  species, 
we  must  further  believe,  "as  a  necessary  consequence,"  that 
it  has  given  origin  to  all  species- 

The  above  reply,  which  is  here  quoted  verbatim  from 
Nature,  Vol.  38,  p.  616-18,  proceeded  to  show  that  it  does 
not  belong  to  "  the  first  principles  of  the  theory  of  natural 
selection  "  to  deny  that  no  other  cause  than  natural  selection 
can  possibly  be  concerned  in  the  origin  of  species ;  and  facts 
were  given  to  prove  that  such  unquestionably  has  been 
the  case  as  regards  the  origin  of  "local"  or  "permanent" 
varieties.  Yet  such  varieties  are  what  Darwin  correctly 
terms  "  incipient "  species,  or  species  in  process  of  taking 
origin.  Therefore,  if  Professor  Huxley's  criticism  is  to  stand 
at  all,  we  must  accept  it  "  as  a  necessary  consequence  of  the 
theory  of  selection,"  that  every  such  variety  "  which  exists, 
exists  in  virtue  of  adaptation  " — a  statement  which  is  proved 
to  be  untrue  by  the  particular  cases  forthwith  cited.  But  as 
this  point  has  been  dealt  with  much  more  fully  in  the  text  of  the 
present  treatise,  I  shall  sum  up  the  main  points  in  a  few  words. 

The  criticism  is  all  embodied  in  two  propositions — namely, 
{a)  that  the  theory  of  natural  selection  carries  with  it,  as 
a  "  necessary  consequence,"  the  doctrine  that  survival  of  the 
fittest  has  been  the  cause  of  the  origin  of  all  species ;  and 
{b)  that  therefore  it  amounts  to  one  and  the  same  thing 
whether  we  dtfine  the  theory  as  a  theory  of  species  or  as 
a  theory  of  adaptations.  Now,  as  a  mere  matter  of  logical 
statement,  it  appears  to  me  that  both  these  propositions  are 
unsound.  As  regards  the  first,  if  we  hold  with  Darwin  that 
other  causes  have  co-operated  with  natural  selection  in  the 
O'.igination  of  some  (i.  e.  many)  species,  it  is  clearly  no  part 
of  the  theorv  of  natural  selection  to  assume  that  none  of 


Appendix  II. 


3" 


i  i 


these  causes  can  ever  have  acted  independently.  In  point 
of  fact,  as  we  have  seen  in  the  foregoing  chapters,  such  has 
probably  and  frequently  been  the  case  under  the  influences 
of  isolation,  climate,  food,  sexual  selection,  and  laws  of 
growth ;  but  I  may  here  adduce  some  further  remarks  with 
regard  to  yet  another  possible  cause.  If  the  Lamarckian 
principles  are  valid  at  all,  no  reason  can  be  shown  why  in 
some  cases  they  may  not  have  been  competent  of  themselves 
to  induce  morphological  changes  of  type  by  successive 
increments,  until  a  transmutation  of  species  is  effected  by 
their  action  alone — as,  indeed,  Weismann  believes  to  have 
been  the  case  with  all  the  species  of  Protozoa  ^  That  such 
actually  has  often  been  the  case  also  with  numberless  species 
of  Melozoa,  is  the  belief  of  the  neo-Lamarckians ;  and 
whether  they  are  right  or  wrong  in  holding  this  belief,  it  is 
equally  certain  that,  as  a  matter  of  logical  reasoning,  they  are 
not  compelled  by  it  to  profess  any  disbelief  in  the  agency  of 
natural  selection.  They  may  be  mistaken  as  to  the  facts,  as 
Darwin  in  a  lesser  degree  may  have  been  similarly  mistaken ; 
but  just  as  Darwin  has  nowhere  committed  himself  to  the 
statement  that  all  species  must  necessarily  have  been  originated 
by  natural  selection,  so  these  neo-Lamarckians  are  perfectly 
logical  in  holding  that  some  species  may  have  been  wholly 
caused  by  the  inheritance  of  acquired  characters,  as  other 
species  may  have  been  wholly  cau  ?d  by  the  natural  selection 
of  congenital  characters.  In  short,  unless  we  begin  by 
assuming  (with  Wall'  :e  and  against  Darwin)  that  there 
can  he  no  other  cause  of  the  origin  of  species  than  that  which 
is  furnished  by  natural  selection,  we  have  no  basis  for 
Professor  Huxley's  statement  **  that  every  species  has  been 
originated  by  selection  " ;  while,  if  we  do  set  out  with  this 
assumption,  we  end  in  a  mere  tautology.  What  ought  to 
be  done  is  to  prove  the  validity  of  this  assumption ;  but,  as 

*  Since  the  above  was  written  Professor  Weismann  has  liansferred 
this  doctrine  from  the  Protozoa  to  their  ancestors. 


» 


312         DarwiUf  and  after  Darwin, 


^?  '■■* 

In 


\" 


Professor  Huxley  makes  no  attempt  to  do  this,  his  criticism 
amounts  to  mere  begp;ing  of  the  question. 

And  now,  as  regards  the  second  point  {b),  even  if  we  grant 
the  assumption  that  natural  selection  is  the  only  possible 
cause  of  the  origin  of  species — or,  which  is  the  same  thing, 
that  every  species  has  been  originated  by  natural  selection, — is 
it  likewise  the  same  thing  whether  we  define  the  theory  of 
natural  selec'ion  as  a  theory  of  species  or  as  a  theory  of 
adaptations  ?  Professor  Huxley's  criticism  endeavours  to  show 
that  it  is ;  but  a  little  consideration  is  enough  to  show  that  it 
is  not.  What  does  follow  from  the  assumption  is,  that,  so  far 
as  specific  characters  are  concernedy  it  is  one  and  the  same  thing 
to  say  that  the  theory  is  a  theory  of  species,  and  to  say  that 
it  is  a  theory  of  adaptations.  But  specific  characters  are  not 
conterminous  with  adaptive  characters;  for  innumerable 
adaptive  characters  are  not  distinctive  of  species,  but  of 
genera,  families,  orders,  classes,  and  -ub-kingdoms.  There- 
fore, if  it  is  believed  (as,  of  course,  Professor  Huxley 
believes)  that  the  theory  in  question  explains  the  evolution 
of  all  adaptive  characters,  obviously  it  is  not  one  and  the 
same  thing  to  define  it  indiiTerently  as  a  theory  of  species  or 
as  a  theory  of  adaptations. 

Now,  all  this  is  not  merely  a  matter  of  logic  chopping.  On 
the  contrary,  the  question  whether  we  are  to  accept  or  to 
reject  the  deduction  that  all  species  must  necessarily  have 
owed  their  origin  to  natural  selection,  is  a  question  of  no 
small  importance  to  the  general  theory  of  evolution.  And 
our  answer  to  this  question  must  be  determined  by  that 
which  we  give  to  the  ulterior  question — Is  the  theory  of 
natural  selection  to  be  defined  as  a  theory  of  species,  or 
as  a  theory  of  adaptations  ? 


We  now  pass  on  to  our  consideration  of  Darwin's  opinion 
touching  the  question,  as  stated  by  himself, — "  The  doctrine 
of  utility,  how  far  true  ? "    As  I  cannot  ascertain  that  Darwin 


Appendix  II. 


313 


has  anywhere  expressed  an  opinion  as  to  whetlier  natural 
selection  has  been  necessarily  concerned  in  the  origin  of  all 
species,  the  issue  here  is  as  to  whether  he  held  this  with 
regard  to  all  specific  characters.  It  will  be  remembered  that 
while  opposing  this  doctrine  as  erroneous  both  in  logic  and 
in  fact,  I  have  represented  that  it  is  not  a  doctrine  which 
Darwin  sanctioned ;  but,  on  the  contrary,  that  it  is  one 
which  he  expressly  failed  to  sanction,  by  recognizing  the 
frequent  inutility  of  specific  characters.  .  Wallace,  on  the 

other  hand,  alleges  that  Darwin  did  bcL^ve  in  the  universal — 
as  distinguished  from  the  general — utility  of  such  characters. 
And  he  adds  that  he  has  "  looked  in  vain  in  Mr.  Darwin's 
works  "  for  any  justification  of  my  statements  to  the  contrary  ^ 
Therefore  I  will  endeavour  to  show  that  Mr.  Wallace's  search 
has  not  been  a  very  careful  one. 

We  must  remember,  however,  that  it  was  not  until  the 
appearance  of  my  paper  on  Physiological  Selection,  four 
years  after  Darwin's  death,  that  the  question  now  in  debate 
was  raised.  Consequently,  he  never  had  occasion  to  deal 
expressly  with  this  particular  question — viz.  whether  "  the 
doctrine  of  utility"  has  any  peculiar  reference  to  specific 
characters — as  he  surely  would  have  done  had  he  entertained 
the  important  distinction  between  specific  and  all  other 
characters  which  Mr.  Wallace  now  alleges  that  he  did 
entertain.  But,  be  this  as  it  may,  we  cannot  expect 
to  find  in  Darwin's  writings  any  express  allusion  to  a 
question  which  had  not  been  raised  until  1886.  The 
most  we  can  expect  to  find  are  scattered  sentences  which 
prove  that  the  distinction  in  question  was  never  so  much 
as  present  to  his  mind, — i.  e.  never  occurred  to  him  as 
even  a  possible  distinction. 

*  Darwinism,  p.  131.  He  says: — "I  have  looked  in  vain  in 
Mr.  Darwin's  works  for  any  such  acknowleclgement  "  (i.e.  "that  a  large 
proiiortion  of  specilic  distinctions  must  be  conceded  useless  to  the  specie- 
presenting  them  "). 


! 

f 


314         Darwin  J  and  after  Darwin, 


IN 


I  will  first  take  the  passages  which  Mr.  Wallace  him- 
self supplies  from  among  those  which  I  had  previously 
indicated. 

"  But  when,  from  the  nature  of  the  organism  and  of  the 
conditions,  modi  ications  have  been  induced  which  are  unim- 
portant for  the  well  are  of  the  species^  they  may  be,  and  ap- 
parently often  have  been,  transmitted  in  nearly  the  same  state 
to  numerous,  otherwise  modified,  descendants  ^" 

On  this  passage  Mr.  Wallace  remarks  that  the  last  five 
words  "clearly  show  that  such  characters  are  usually  not 
'  specific,'  in  the  sense  that  they  are  such  as  distinguish 
species  from  one  another,  but  are  found  in  numerous  allied 
species."  But  I  cannot  see  that  the  passage  shows  anything 
of  the  sort.  What  to  my  mind  it  does  show  is,  (a)  that 
Mr.  Darwin  repudiated  Mr.  Wallace's  doctrine  touching  the 
necessary  utility  of  all  sf)ecific  characters :  {b)  that  he  takes 
for  granted  the  contrary  doctrine  touching  the  inutility  of 
some  specific  characters:  (c)  that  without  in  this  place 
alluding  to  the  proportional  number  of  useless  specific 
characters,  he  refers  their  origin  in  some  cases  to  "  the 
nature  of  the  organism"  (i.e.  "spontaneous  variability"  due 
to  internal  causes),  and  in  other  cases  to  "  the  conditions  " 
(i.  e.  variability  induced  by  external  causes) :  (d)  that  when 
established  as  a  specific  character  by  heredity,  such  a  useless 
character  was  held  by  him  not  to  tend  to  become  obsolete  by 
the  influence  of  natural  selection  or  any  other  cause  ;  but,  on 
the  contrary,  to  be  "  transmitted  in  nearly  the  same  state  to 
numerous,  otherwise  modified,  descendants  " — or  progeny  of 
the  species  in  genera,  families,  &c. :  {e)  and,  therefore,  that 
useless  characters  which  are  now  distinctive  of  genera, 
lamilies,  &c.,  were  held  by  him  frequently,  if  not  usually,  to 
point  to  uselessness  of  origin,  when  first  they  arose  as  merely 
specific  characters.  Even  the  meaning  which  Mr.  Wallace 
reads  into  this  passage  must  imply  every  one  of  these  points ; 

*  Origin  of  Species,  p.  175.     Italics  mine. 


Appendix  II. 


315 


and  therefore  I  do  not  see  that  he  gains  much  by  apparently 
seeking  to  add  this  further  meaning — viz.  that  in  Darwin's 
opinion  there  must  have  beeti  some  unassignable  reason 
preventing  the  occurrence  of  useless  specific  characters  in 
cases  where  species  are  noi  destined  to  become  the  parents 
of  genera. 

Moreover,  any  such  meaning  is  out  of  accordance  with 
the  context  from  which  the  passage  is  taken.  For,  after 
a  long  consideration  of  the  question  of  utility,  Darwin  sums 
up, — "  We  thus  see  that  with  plants  many  morphological 
changes  may  be  attributed  to  the  laws  of  growth  and  the 
interaction  of  parts,  independently  of  natural  selection."  And 
then  he  adds, — '*  From  the  fact  of  the  above  characters  being 
unimportant  for  the  welfare  of  the  apecies,  any  slight  variations 
which  occurred  in  them  would  not  have  been  augmented 
through  natural  selection.^'  Again,  still  within  the  same 
passage,  he  says,  while  alluding  to  the  s.auses  other  than 
natural  selection  which  lead  to  changes  of  specific  characters, — 
"If  the  unknoivn  cause  were  to  act  almost  uniformly  for 
a  length  of  time,  we  may  infer  that  the  result  would  be 
almost  uniform ;  and  in  this  case  all  the  individuals  of  the 
species  would  be  modified  in  the  same  manner."  For  my 
own  part  I  do  not  understand  how  Mr.  Wallace  can  have 
overlooked  these  various  references  to  species^  all  of  which 
occur  on  the  very  page  from  which  he  is  quoting.  The 
whole  argument  is  to  show  that  "many  morphological 
changes  may  be  attributed  to  the  laws  of  growth  and  the 
inter-action  of  parts  \^plus  external  conditions  of  life], 
independently  of  natural  selection  " ;  that  such  non-adaptive 
changes,  when  they  occur  as  "  specific  characters,"  may,  if 
the  species  should  afterwards  give  rise  to  genera,  families, 
&c.,  become  distinctive  of  these  higher  divisions.  But  there 
is  nothing  here,  or  in  any  other  part  of  Darwin's  writings, 
to  countenance  the  inconsistent  notion  which  Mr.  Wallace 
appears  to  entertain, — viz.  that  species  which  present  useless 


;    > 


!'       ■ 


'^s= 


b 

K. 


I'-' 
Ik  * 


Is- 


316         Darwin,  and  after  Darwin, 

characters  are  more  apt  to  give  rise  to  genera,  families,  &c., 
than  are  species  which  do  not  present  such  characters. 

The  next  passage  which  Mr.  Wallace  quotes,  with  his 
comments  thereon,  is  as  follows.    The  italics  are  his. 

"'Thus  a  large  yet  undefined  extension  may  safely  be  given 
to  the  direct  and  indirect  results  of  natural  selection  ;  but  I 
now  admit,  after  reading  the  essay  of  Nageli  on  plants,  and 
the  remarks  by  various  authors  with  respect  to  animals,  more 
especially  those  recently  made  by  Professor  Broca,  that  in 
the  earlier  editions  of  my  Origin  of  Species  I  perhaps  attri- 
buted too  much  to  the  action  of  natural  selection,  or  the  sur- 
vival of  the  fittest.  I  have  altered  the  fifth  edition  of  the 
Origin  so  as  to  confine  my  remarks  to  adaptive  changes  of 
structure ;  but  I  am  convinced^  from  the  light  gained  during 
even  the  last  few  yearsy  that  very  many  structures  which  now 
appear  to  be  useless,  will  hereafter  be  proved  to  be  useful, 
and  will  therefore  come  within  the  range  of  natural  selection. 
Nevertheless  I  did  not  formerly  consider  sufficiently  the  exis- 
tence of  structures  which,  as  far  as  we  can  at  present  judge, 
are  neither  beneficial  nor  injurious ;  and  this  I  believe  to  be 
one  of  the  greatest  oversights  &s  yet  detected  in  my  work.' 

Now  it  is  to  be  remarked  vhat  neither  in  these  passages 
nor  in  any  of  the  other  less  distinct  expressions  of  opinion  on 
this  question,  does  Darwin  ever  admit  that  "  specific  ciiaracters  " 
—that  is,  the  particular  characters  which  serve  to  distinguish 
one  species  from  another — are  ever  useless,  much  less  that 
"a  large  proportion  of  them"  are  so,  as  Mr  Romanes  makes 
him  "freely  acknowledge."  On  the  other  hand,  in  the  passage 
which  I  have  italicised  he  strongly  expresses  his  view  that 
much  of  what  we  suppose  to  be  useless  is  due  to  our  ignor- 
ance ;  and  as  I  hold  myself  that,  as  regards  many  of  the  sup- 
posed useless  characters,  this  is  the  true  explanation,  it  may 
be  well  to  give  a  brief  sketch  of  the  progress  of  knowledge 
in  transferring  characters  from  the  one  category  to  the  other'." 

It  is  needless  to  continue  this  quotation,  because  ot  course 
no  one  is  disputing  that  an  enormous  number  of  specific 


*  Darwinism,  p.  132. 


Appendix  IL 


317 


characters  whose  utility  is  unknown  arc  nevertheless  uselul, 
and  therefore  due  to  natural  selection.  In  other  words, 
the  question  is  not — Are  there  not  many  useful  specific 
characters  whose  utility  is  unknown?  but — Does  it  follow 
from  the  theory  of  natural  selection  that  all  specific 
characters  must  necessarily  be  useful  ?  Well,  it  appears  to 
me  that  without  going  further  than  the  above  passage, 
which  Mr.  Wallace  has  quoted,  we  can  see  clearly  enough 
what  was  Darwin's  opinion  upon  the  subject.  He  did  not 
believe  that  it  followed  deductively  from  his  theory  that  all 
specific  characters  must  necessarily  be  useful;  and  therefore 
he  regarded  it  as  a  question  o\  fad — to  be  determined 
by  induction  as  distinguished  from  deduction — in  what 
proportional  number  of  cases  they  are  so.  Moreover  he 
gives  it  as  his  more  matun  .1  opinion,  that,  "as  far  as  we  can 
at  present  judge "  (i.e.  from  the  present  state  of  observation 
upon  the  subject :  if,  with  Mr.  Wallace,  his  judgement  were 
a  priori,  why  this  qualification  ?),  he  had  not  previously 
sufficiently  considered  the  existence  of  non-adaptive  characters 
— and  this  he  ended  by  believing  was  one  of  the  greatest 
oversights  as  yet  detected  in  his  work.  To  me  it  has  always 
seemed  that  this  passage  is  one  of  the  greatest  exhibitions  of 
candour,  combined  with  solidity  of  judgement,  that  is  to  be 
met  with  even  in  the  writings  of  Darwin.  There  is  r>o  talk 
about  any  deductive  "  necessity  " ;  but  a  perfect  readiness  to 
allow  that  causes  other  than  natural  selection  may  have  been 
at  work  in  evoking  non-adaptive  characters,  so  that  the  fifth 
edition  of  the  Origin  of  Species  was  altered  in  order  to 
confine  the  theory  of  natural  selection  to  "adaptive  changes" 
— i.e.  to  constitute  it,  as  I  have  said  in  other  words, 
"a  theory  of  the  origin,  or  cumulative  development,  of 
adaplaliotts." 

If  to  this  it  be  said  that  in  the  above  passage  there 
is  no  special  mention  of  species,  the  quibble  would  admit 
ot   a  threeiold   reply.     In   the   first   place,  the   quibble  in 


it 


318        Darwin^  and  after  Darwin. 

question  had  never  been  raised.  As  already  stated,  it  is 
only  since  the  appearance  of  my  own  paper  on  Physiological 
Selection  that  anybody  ever  thought  of  drawing  a  distinction 
between  species  and  genera,  such  that  while  all  specific  char- 
acters must  be  held  necessarily  useful,  no  such  necessity  extends 
to  generic  characters.  In  the  second  place,  that  Darwin  must 
have  had  specific  characters  (as  well  as  generic)  in  his  mind 
when  Willing  the  above  passage,  is  rendered  unquestionable 
by  the  fact  that  many  of  the  instances  of  inutility  adduced  by 
Nageli  and  Broca  have  reference  to  specific  characters. 
Lastly,  as  shown  in  the  passages  previously  quoted  from  the 
sixth  edition  of  the  Origin  of  Species,  Darwin  attributed  the 
origin  of  useless  generic  characters  to  useless  specific 
characters ;  so  that  Mr.  Wallace  really  gains  nothing  by  his 
remark  that  specific  characters  are  not  specially  mentioned 
in  the  present  passage. 
Once  more: — 

"Darwin's  latest  expression  of  opinion  on  this  question  is 
interesting,  since  it  shows  he  was  inclined  to  return  to  his 
earlier  view  of  the  general,  or  universal,  utility  of  specific 
characters '." 

This  "  latest  expression  of  opinion,"  as  I  shall  immediately 
prove,  shows  nothing  of  the  kind — being,  in  fact,  a  mere 
re-statement  of  the  opinion  everywhere  and  at  all  times 
expressed  by  Darwin,  touching  the  caution  that  must  be 
observed  in  deciding,  with  respect  to  individual  cases,  whether 
an  apparently  useless  specific  character  is  to  be  regarded  as 
really  useless.  Moreover,  at  no  time  and  in  no  place  did 
Darwin  entertain  any  "view  of  the  general,  or  universal, 
utility  of  specific  characters."  But  the  point  now  is,  that  if 
(as  was  the  case)  Darwin  "inclined"  to  depart  more  and 
more  from  his  earlier  view  of  the  highly  general  utility  of 
specific  characters ;  and  if  (as  was  not  the  case)  he  ended  by 
showing  an  inclination  "  to  return  "  to  this  earlier  view ;  what 

*  Darwinism,  p.  14a. 


Appendix  II. 


319 


becomes  of  the  whole  of  Mr.  Wallace's  contention  against 
which  this  Appendix  is  directed,  namely,  that  Darwin  never 
entertained  any  other  view  than  that  of  the  ^^gene^al,  or 
universal  J  utility  0/  specific  characters"  "i 

The  ^'  latest  expression  of  opinion  "  which  Mr.  Wallace 
quotes,  occurs  in  a  letter  written  to  Professor  Semper  in 
1878.     It  is  as  follows  : — 

"As  our  knowledge  advances,  very  slight  differences,  con- 
sidered by  systematists  as  of  no  importance  in  structure,  aiu 
continually  found  to  be  functionally  important ;  and  I  have 
been  especially  struck  with  this  fact  in  the  case  of  plants,  to 
which  my  observations  have  of  late  years  been  confined.  There- 
fore it  seems  to  me  rather  rash  to  consider  the  slight  differ- 
ences between  representative  species,  for  instance  those  in- 
habiting the  different  islands  of  the  same  archipelago,  as  of 
no  functional  importance,  and  as  not  in  any  way  due  to  natural 
selection  *." 

Now,  with  regard  to  this  passage  it  is  to  be  observed,  as 
already  remarked,  that  it  refers  to  the  formation  of  final 
judgements  io\.\c\\\n^ particular  cases :  there  is  nothing  to  show 
that  the  writer  is  contemplating  general  principles,  or  advo- 
cating on  deductive  grounds  the  dogma  that  specific  char- 
acters must  be  necessarily  and  universally  adaptive  characters. 
Therefore,  what  he  here  says  is  neither  more  nor  less  man 
I  have  said.  For  I  have  always  held  that  it  would  be  "  rather 
rash"  to  conclude  that  any  giva  cases  of  apparent  inutility 
are  certainly  cases  of  real  inutility,  merely  on  the  ground  that 
utility  is  not  perceived.  But  this  is  clearly  quite  a  distinct 
matter  from  resisting  the  a  priori  generalization  that  all  cases 
of  apparent  inutility  must  certainly  be  cases  of  real  utility. 
And,  I  maintain,  in  every  part  of  his  writings,  without  any 
exception,  where  Darwin  alludes  to  this  matter  of  general 
principle,  it  is  in  terms  which  directly  contradict  the  de- 
duction in  question.     As  the  whole  of  this  Appendix  has 

'  Life  and  Letters,  vol.  ill.  p.  161 . 


'N    1: 


hi** 


IS"* 


4 


320         Darwin,  and  after  Darwin, 

been  directed  to  proving  that  such  is  the  case,  it  will  now, 
I  think,  be  sufficient  to  supply  but  one  further  quotation,  in 
order  to  show  that  the  above  "latest  expression  of  opinion," 
far  from  indicating  that  in  his  later  years  Darwin  "  inclined  " 
10  Mr.  Wallace's  views  upon  this  matter,  is  quite  compatible 
with  a  distinct  "  expression  of  opinion  "  to  the  contrary,  in 
a  letter  written  less  than  six  years  before  his  death. 

"  In  my  opinion  the  greatest  error  which  I  have  committed^ 
has  been  not  allowing  sufficient  weight  to  the  direct  action  of 
the  environment,  i.e.  food,  climate,  &c.,  independently  o/natural 
selection.  Modifications  thus  caused,  which  are  neither  of 
advantage  nor  disadvantage  to  the  modified  organisms,  would 
be  especially  favoured,  as  I  can  now  see  chiefly  through 
your  observations,  by  isolation  in  a  small  area,  where  only 
a  few  individuals  lived  under  nearly  uniform  conditions'^* 

I  will  now  proceed  to  quote  further  passages  from 
Darwin's  works,  which  appear  to  have  escaped  the  notice  of 
Mr.  Wallace,  inasmuch  as  they  admit  of  no  doubt  regarding 
the  allusions  being  to  specific  characters. 

"  We  may  easily  err  in  attributing  importance  to  chaj'acters^ 
and  in  believing  that  they  have  been  developed  through  natural 
selection.  We  must  by  no  means  overlook  the  effects  of  the 
derinite  action  of  changed  conditions  of  life, — of  so-called 
spontaneous  variations,  which  seem  to  depend  in  a  quite 
subordinate  degree  on  the  nature  of  the  conditions, — of  the 
tendency  to  reversion  to  long-lost  characters, — of  the  complex 
laws  of  growth,  such  as  of  correlation  ^  compensation,  of 
pressure  of  one  part  on  another,  &c.,  and  finally  of  sexual 
selection,  by  which  characters  of  use  to  one  sex  are  often 
gained  and  then  transmitted  more  or  less  perfectly  to   the 

*  Life  and  Letters,vo\.  iii.  p.  158. 

'  It  must  be  observed  that  Darwin  uses  this  word,  not  as  Mr.  Wallace 
always  uses  it  (viz.  as  if  correlation  can  only  be  with  regard  to  adaptive 
characters;,  but  in  the  wider  sense  that  any  chant^e  in  one  part  i)f  an 
organism — whether  or  not  it  happens  to  be  an  adaptive  change — is  apt 
to  induce  changes  iu  other  parts. 


!!;,  \ 


Appendix  II, 


321 


other  sex,  though  of  no  use  to  this  sex.  But  structures  thus 
indirectly  gained,  althotigh  at  first  of  no  adv>uitage  to  a  s^ectfs, 
may  subsequently  have  been  taken  advantaj^e  of  by  its  modified 
descendants,  under  new  conditions  of  life  and  newly  acquired 
habits  V 

It  appeared — and  still  appears — to  me,  that  where  so  many 
causes  are  expressly  assigned  as  producino^  useless  specific 
characters,  and  that  some  of  them  (such  as  climatic  influences 
and  independent  variability)  must  be  highly  general  in  their 
action,  I  was  justified  in  representing  it  as  Darwin's  opinion 
that  "a  large  proportional  number  of  specific  characters" 
are  useless  to  the  species  presenting  them,  although  after- 
wards they  may  sometimes  become  of  use  to  genera,  families, 
&c.  Moreover,  this  passage  goes  on  to  point  out  that 
specific  characters  which  at  first  sight  appear  to  be  obviously 
useful,  are  sometimes  found  by  fuller  knowledge  to  be  really 
useless — a  consideration  which  is  the  exact  inverse  of  the 
argument  from  ignorance  as  used  by  Mr.  Wallace,  and 
serves  still  further  to  show  that  in  Darwin's  opinion  utility  is 
by  no  means  an  invariable,  still  less  a  "necessary,"  mark  of 
specific  character.  The  following  are  some  of  the  instances 
which  he  gives. 

"  The  sutures  in  the  skulls  of  young  mammals  have  been  ad- 
vanced as  a  beautiful  adaptation  for  aiding  parturition,  and  no 
doubt  they  may  facilitate,  or  be  indispensable  for  this  act  ; 
but  as  sutures  occur  in  the  skulls  of  young  birds  and  reptiles, 
which  have  only  to  escape  from  a  broken  egg,  we  may  infer 
that  this  structure  has  arisen  from  the  laws  of  growth,  and 
has  been  taken  advantage  of  in  the  parturition  of  the  higher 
animals  "." 

"  The  naked  s'vin  on  the  head  of  a  vulture  is  generally  con- 
sidered as  a  direct  adaptation  for  wallowing  in  putridity; 
and  so  it  may  be,  or  it  may  possibly  be  due  to  the  direct 
action  of  the  putrid  matter ;  but  we  should  be  very  cautious 


V  I 


II. 


*  Origin  of  Species ^  pp.  i57-8. 

Y 


Ibid. 


322         Darwifij  and  after  Darwin, 


I  k 


'1; 
f 


b 


k^ 


in  drawing  any  such  inference  [i.e.  as  to  utility]  when  we  see 
the  skin  on  the  head  of  the  clean-feeding  male  Turkey  is 
likewise  naked  V 

Similarly,  in  the  Descent  of  Man  it  is  said  : — 

"  Variations  of  the  same  general  nature  have  often  been  taken 
advantage  of  and  accumulated  through  sexual  selection  in  re- 
lation to  the  propagation  of  the  species,  and  through  natural 
selection  in  relation  to  the  general  purposes  of  life.  Kence, 
secondary  sexual  characters,  when  equally  transmitted  to  both 
sexes,  can  be  distinguished  from  ordinary  specific  chat  acters, 
only  by  the  light  of  analogy.  The  modifications  acquired 
through  sexual  selection  are  often  so  strongly  pronounced 
that  the  two  sexes  have  frequently  been  ranked  as  distinct 
species,  or  even  as  distinct  genera  ^" 

As  Mr,  Wallace  does  not  recognize  sexual  selection,  he 
incurs  the  burden  of  proving  utility  (in  the  life-preserving 
sense)  in  all  these  "  frequently  "  occurring  cases  where  there 
are  such  '*  strongly  pronounced  modifications,"  and  we  have 
already  seen  in  the  text  his  manner  of  dealing  with  this 
burden.  But  the  point  here  is,  that  whether  or  not  we 
accept  the  theory  of  sexual  selection,  we  must  accept 
it  as  Darwin's  opinion — first,  that  in  their  beginnings,  as 
specific  characters,  these  sexual  modifications  were  often 
of  a  merely  ^^ general  nature**  (or  without  reference  to 
utility  even  in  the  life-embellishing  sense),  and  only  after- 
wards "  have  often  been  taken  advantage  of  and  accumu- 
lated through  sexual  selection":  and,  secondly,  that  "we 
know  they  have  been  acquired  in  some  instances  at  the 
coit  not  only  of  inconvenience,  but  of  exposure  to  actual 
dangers  ^." 

We  may  now  pass  on  to  some  further,  and  even  stronger, 
expressions  of  opinion  with  regard  to  the  frequent  inutility  of 
specific  characters. 


*  Origin  of  Species,  pp.  157-8. 
^  Descent  of  Man,  p.  615. 


Ibid. 


■'  i 


II 


Appendix  IL 


323 


we 


"  I  have  made  these  remarks  only  to  show  that,  if  we  are  un- 
able to  account  for  the  characteristic  differences  of  our  several 
domestic  breeds,  which  nevertheless  are  generally  admitted  to 
have  arisen  through  ordinary  generation  from  one  or  a  few 
parent  stocks,  we  ought  not  to  lay  too  much  stress  on  our 
ignorance  of  the  precise  cause  [i.e.  whether  natural  selection 
or  some  other  cause]  of  the  slight  analogous  dififerences  between 
true  species.  ...  I  fully  admit  that  many  structures  are  now 
of  no  use  to  their  possessors,  and  may  never  have  been  of 
any  use  to  their  progenitors;  but  this  docs  not  prove  that 
they  were  formed  solely  for  beauty  or  variety.  No  doubt  the 
definite  action  of  changed  conditions,  and  the  various  causes 
of  modification,  lately  specified,  have  all  produced  an  effect, 
probably  a  great  effect^  independently  of  any  advantage  thus 

gained. It  is  scarcely  possible  to  decide  how  much 

allowance  ought  to  be  made  for  such  causes  of  change,  as 
the  definite  act'on  of  external  conditions,  so-called  spontaneous 
variations,  and  the  complex  laws  of  growth  ;  but,  with  these 
iiiiportafit  exceptions^  we  may  conclude  that  the  structure  of 
every  living  creature  either  now  is,  or  formerly  was,  of  some 
direct  or  indirect  use  to  its  possessor*." 

Here  again,  if  we  remember  how  "important"  these 
"  exceptions "  are,  I  cannot  understand  any  one  doubting 
Darwin's  opinion  to  have  been  that  a  large  proportional 
number  of  specific  characters  are  useless.  For  that  it  is 
"  species  "  which  he  here  has  mainly  in  his  mind  is  evident 
from  what  he  says  when  again  alluding  to  the  subject  in 
his  "Summary  of  the  Chapter" — namely,  "In  wawy  other 
cases  [i.e.  in  cases  where  natural  selection  has  not  been 
concerned]  modifications  are  probably  the  direct  result  of 
the  laws  of  variation  or  of  growth,  independently  of  any 
good  having  been  thus  gained."  Now,  not  only  do  these 
"  laws "  apply  as  much  to  species  as  they  do  to  genera ; 
"  but,"  the  passage  goes  on  to  say,  "  even  such  structures 
have  often,  we  may  feel  assured,  been  subsequently  taken 

*  Descent  of  Man,  pp.  159-60. 
Y   % 


324         Darwin^  and  after  Darwin, 


advantage  of,  and  still  furthr:  modified,  for  the  good  of 
species  under  new  condidons  of  life."  Obviously,  there- 
fore, the  inutility  in  such  cases  is  taken  to  have  been  prior 
to  any  utility  subsequently  acquired;  and  genera  are  not 
historically  prior  to  the  species  in  which  they  originate. 
Here  is  another  quotation : — 

"  Thus,  as  I  am  inclined  to  believe,  morphological  differences, 
which  we  consider  as  important— such  as  the  arrangement  of 
the  leaves,  the  divisions  of  the  flower  or  of  the  ovarium,  the 
position  of  the  ovules,  Scc.—Jirst  appeared  in  many  cases  as 
fluctuating  variations,  which  sooner  or  later  became  constant 
through  the  nature  of  the  organism  and  of  the  surrounding 
conditions,  as  well  as  through  the  intercrossing  of  distinct  in- 
dividuals, but  not  through  natural  selection ;  for  as  these 
morphological  characters  do  not  affect  the  welfare  of  the 
specieSy  any  slight  deviations  in  them  could  not  have  been 
governed  or  accumulated  through  this  latter  agency.  It  is  a 
strange  result  which  we  thus  arrive  at,  namely,  that  characters 
of  slight  vital  importance  to  the  species,  are  the  most  im- 
portant to  the  systematist ;  but,  as  we  shall  hereafter  see  when 
we  treat  of  the  genetic  principle  of  classification,  this  is  by 
no  means  so  paradoxical  as  it  may  at  first  appear*." 

Clearly  the  view  here  expressed  is  that  characters  which 
are  now  distinctive  of  higher  taxonomic  divisions  "first 
appeared "  in  the  parent  species  of  such  divisions ;  for 
not  only  would  it  be  unreasonable  to  attribute  the  rise  and 
preservation  of  useless  characters  to  "  fluctuating  variations  " 
affecting  a  number  of  species  or  genera  similarly  and  simul- 
taneously ;  but  it  would  be  impossible  that,  if  such  were  the 
case,  they  could  be  rendered  "constant  through  the  nature 
of  the  organism  and  of  the  surrounding  conditions,  as  well  as 
through  the  intercrossing  of  distinct  individuals  V* 


*  Descent  of  Man,  p.  176. 

'  The   passage  to  which   these  remarks  apply  is  likewise  quoted, 
in  the  same  connexion  as  above,  in  my  paper  on  Physiological  Selection. 


Appendix  IL 


3^0 


the 


>> 


Here  is  another  passage  to  *he  same  general  effect.  In 
ciUuding  to  the  objection  from  inutility  as  advanced  by 
Bronn,  Broca,  and  Nageli,  Mr.  Darwin  says  : — *  There  is 
much  force  in  the  above  objection";  and,  after  again 
pointing  out  the  important  possibility  in  any  particular 
cases  of  hidden  or  former  use,  and  the  action  of  the  laws  of 
growth,  he  goes  on  to  say, — "  In  the  third  place,  we  have 
to  allow  for  the  direct  and  definite  action  of  changed  con- 
ditions of  life,  and  for  so-called  spontaneous  variations,  in 
which  the  nature  of  the  conditions  plays  quite  a  sub- 
ordinate part  ^"  Elsewhere  he  says, — "  It  appears  that  I 
formerly  underrated  the  frequency  and  value  of  these  latter 
forms  of  variation  as  leading  to  permanent  modifications  of 
structure  independently  of  natural  selection  \"  The  "  forms  of 
variation  "  to  which  he  here  alludes  are  "  variations  which 
seem  to  us  in  our  ignorance  to  arise  spontaneously  ';  and 
it  is  evident  that  such  variations  cannot  well  **  arise "  in 
two  or  more  species  of  a  genus  similarly  and  simultane- 
ously, so  as  independently  to  lead  "to  permanent  modifica- 
tions of  structure "  in  two  or  more  parallel  lines.  It  is 
further  evident  that  by  "spontaneous  variations"  Darwin 
alludes  to  extreme  cases  of  spontaneous  departure  from 
the  general  average  of  specific  characters;  and  therefore 
that  lesser  or  more  ordinary  departures  must  be  of  still 
greater  "  frequency." 

Again,  speaking  of  the  principles  of  classification, 
Darwin  writes : — 

"  We  care  not  how  trifling  a  character  may  be— let  it  be  the 
mere  inflection  of  the  angle  of  the  jaw,  the  manner  in  which 

In  criticising  that  paper  in  Nature  (vol.  xxxix.  p.  137),  Mr.  Thiselton 
Dyer  says  of  my  interpretation  of  this  passage,  "  the  obvious  drift  of  this 
does  not  relate  to  specific  differences,  but  to  those  which  are  charac- 
teristic of  family."  But  in  making  this  remark  Mr.  Dyer  could  not 
have  read  the  passage  with  sufficient  care  to  note  the  points  which  I  have 
DOW  explained. 

'  Origin  of  Species,  p.  171.  *  Ibid.  p.  421. 


326        Darwin^  and  after  Darwin, 


'1 

■v 

^3 


an  insect's  wing  is  folded,  whether  the  skin  be  covered  by 
hair  or  feathers -if  it  prevail  throughout  many  and  different 
species,  especially  those  having  very  different  habits  of  life, 
it  assumes  high  value  [i.e.  for  purposes  of  classification],  for 
we  can  account  for  its  presence  in  so  many  forms  with  such 
different  habits,  only  by  inheritance  from  a  common  parent. 
We  may  err  in  this  respect  in  regard  to  single  points  of  structure, 
but  when  several  characters,  let  them  be  ever  so  trifling,  concur 
throughout  a  large  group  of  beings  having  different  habits,  we 
may  feel  almost  sure,  on  the  theory  of  descent,  that  these 
characters  have  been  inherited  from  a  common  ancestor;  and 
we  know  that  such  aggregated  characters  have  especial  value 
in  classification'." 

Now  it  is  evident  that  this  argument  for  the  general 
theory  of  evolution  would  be  destroyed,  if  Wallace's  as- 
sumption of  utility  of  specific  characters  as  universal  were 
to  be  entertained.  And  the  fact  of  apparently  "trifling"' 
characters  occurring  throughout  a  large  group  of  beings 
"  having  different  habits  "  is  proof  that  they  are  really  trifling, 
or  without  utilitarian  significance. 

It  is  needless  to  multiply  these  quotations,  for  it  appears 
to  me  that  the  above  are  amply  sufficient  to  establish 
the  only  point  with  which  we  are  here  concerned,  namely, 
that  Darwin's  opinion  on  the  subject  of  utility  in  relation 
to  specific  characters  was  substantially  identical  with  my 
own.  And  this  is  established,  not  merely  by  the  literal 
meaning  of  the  sundry  passages  here  gathered  together 
from  different  parts  of  his  writings;  but  likewise,  and  per- 
haps still  more,  from  the  tone  of  thought  which  pervades 
these  writings  as  a  whole.  It  requires  no  words  of  mine 
to  show  that  the  literal  meaning  of  the  above  quotations 
is  entirely  opposed  to  Mr.  Wallace's  view  touching  the 
necessary  utility  of  all  specific  characters;  but  upon  the 
other  point — or  the  general  tone  of  Mr.  Darwin's  thought 
regarding  such  topics — it  may  be  well  to  add  two  remarks. 

*  Origin  of  Species,  pp.  373-373' 


Appendix  IL 


327 


In  the  first  place,  it  H'ust  be  evident  that  so  soon  as 
we  cease  to  be  bound  by  any  a  priori  deduction  as  to 
natural  selection  being  "  the  exclusive  means  of  modifica- 
tions," it  ceases  to  be  a  matter  of  much  concern  to  the  theory  of 
natural  selection  in  what  proportion  other  means  of  modifi- 
cation have  been  at  woric— especially  when  non-adaptive 
modifications  are  concerned,  and  where  these  have  refer- 
ence to  merely  "specific  characters,"  or  modifications  of 
the  most  incipient  kind,  least  generally  diffused  among 
organic  types,  and  representing  the  incidence  of  causes  of 
less  importance  than  any  others  in  the  process  of  organic 
evolution  considered  as  a  whole.  Consequently,  in  the 
second  place,  we  find  that  Darwin  nowhere  displays  any 
solicitude  touching  the  proportional  '.mm her  of  specific  char- 
acters that  may  eventually  prove  to  be  due  to  causes  other 
than  natural  selection.  He  takes  a  much  wider  and 
deeper  view  of  organic  evolution,  and,  having  entirely 
emancipated  himself  from  the  former  conception  of 
species  as  the  organic  units,  sees  virtually  no  significance 
in  specific  characters,  except  in  so  far  as  they  are  also 
adaptive  characters. 

Such,  at  ail  events,  appears  to  me  the  obvious  interpretation 
of  his  writings  when  these  are  carefully  read  with  a  view  to 
ascertaining  his  ideas  upon  "Utilitarian  doctrine:  how  far 
true."  And  I  make  these  remarks  because  it  has  been  laid 
to  my  charge,  that  in  quoting  such  passages  as  the  above  I 
have  been  putting  "  a  strained  interpretation  "  upon  Darwin's 
utterances :  "  such  admissions,"  it  is  said,  "  Mr.  Romanes 
appears  to  me  to  treat  as  if  wrung  from  a  hostile  witness  \" 
But,  from  vaat  has  gone  before,  it  ought  to  be  apparent 
that  I  take  precisely  the  opposite  view  to  that  here  imputed. 
Far  from  deeming  these  and  similar  passages  as  "  admissions 
wrung  from    a    hostile    witness,"   and    far    from    seeking 


*  Mr.  Thiselton  Dyer  in  Nature,  loc.  cit, 


p 

W 

f 


pi 

I'll 


i 


328         Darwirif  and  after  Darwin. 

to  put  any  "  strained  interpretation "  upon  them,  I  believe 
tliat  they  are  but  the  plain  and  unequivocal  expressions 
of  an  opinion  which  I  have  always  understood  that 
Darwin  held  And  if  any  one  has  been  led  to  think  other- 
wise, I  throw  back  this  charge  oi  "  strained  interpretation," 
by  challenging  such  a  person  to  adduce  a  single  quotation 
from  any  part  of  Darwin's  works,  which  can  possibly  be 
held  to  indicate  that  he  regarded  passages  like  those 
above  quoted  as  in  any  way  out  of  conformity  with  his 
theory  of  natural  selection — or  as  put  forward  merely 
to  "admit  the  possibility  of  explanations,  to  wh'ch  really, 
however,  he  did  not  attach  much  importance."  To  the 
best  of  my  judgement  it  is  only  some  bias  in  favour  of 
Mr.  Wallace's  views  that  can  lead  a  naturalist  to  view  in 
this  way  the  clear  and  consistent  expression  of  Darwin's. 

That  Mr.  Wallace  himself  should  be  biassed  in  this  matter 
might,  perhaps,  be  expected.  After  rendering  the  following 
very  unequivocal  passage  from  the  Origin  of  Species  (p.  72) — 
"  There  can  be  little  doubt  that  the  tendency  to  vary  in  the 
same  manner  has  ofteii  been  so  strong,  that  all  individuals  of 
the  same  species  have  been  similarly  modified  without  the  aid  of 
any  form  of  selection'" — Mr.  Wallace  says,  "But  no  proof 
whatever  is  offered  of  this  statement,  and  it  is  so  entirely 
opposed  to  all  we  know  of  the  facts  oi"  variation  as  given  by 
Darwin  himself,  that  the  important  word  '  all '  is  probably  an 
oversight."  But,  If  Mr.  Wallace  had  read  the  very  next 
sentence  he  would  have  seen  that  here  the  important 
word  "all"  could  not  possibly  have  been  "an  oversight." 
For  the  passage  continues, — "  Or  only  a  third,  fifth,  or  tenth 
part  of  the  individuals  may  have  been  thus  affected,  of  which 
fact  several  instances  could  be  given.  Thus  Graba  estimates 
;hat  about  one-fifth  of  the  guillemots  in  the  Faroe  Islands 
consist  of  a  variety  so  well  marked,  that  it  was  formerly 
ranked  as  a  distinct  species  under  the  name  of  Uria 
lacrymans."     And  even  if  this  passage  had  not  been  thus 


'  .r 


Appendix  II. 


329 


specially  concerned  with  the  question  of  the  proportion  in 
which  "  individuals  of  the  same  species  have  been  similarly 
modified  without  the  aid  of  any  form  of  selection"  the  oversight 
with  respect  to  "  the  imporiani  word  '  all '  "  would  siill  have 
remained  an  oversight  of  a  recurrent  character,  as  the  fol- 
lowing additional  quotations  from  other  parts  of  Darwin's 
writings  may  perhaps  render  apparent. 

"  There  must  be  some  efficient  cause  for  each  slight  individual 
difference,  as  well  as  for  more  strongly  marked  variations 
which  occasionally  arise ;  and  if  the  unknown  cause  were  to 
act  persistently,  it  is  almost  certain  that  all  the  individuals 
of  the  species  would  be  similarly  modified'." 

"  The  acquisition  of  a  useless  part  can  hardly  be  said  to 
raise  an  organism  in  the  natural  scale We  are  so  igno- 
rant of  the  exciting  cause  of  the  above  specified  modifications ; 
but  if  the  unknown  cause  were  to  act  almost  uniformly  for  a 
length  of  time,  we  may  infer  that  the  result  would  be  almost 
uniform ;  and  in  this  case  all  the  individuals  of  the  species 
would  be  modified  in  the  same  manner'." 

Moreover,  when  dealing  even  with  such  comparatively 
slight  changes  as  occur  between  our  domesticated  varieties — 
and  which,  a  fortiori^  are  less  likely  to  become  "  stable " 
through  the  uniform  operation  of  causes  other  than  selec- 
tion, seeing  that  they  are  not  only  smaller  in  amount  than 
occurs  among  natural  species,  but  also  have  had  but  a 
comparatively  short  time  in  which  to  accumulate — Darwin 
is  emphatic  in  his  assertion  of  the  same  principles.  For 
instance,  in  the  twenty-third  chapter  of  the  Variation  of 
Plants  and  Animals  under  Domestication^  he  repeatedly 
uses  the  term  "  definite  action  of  external  conditions,"  and 
begins  the  chapter  by  explaining  his  use  of  the  term 
thus : — 

"  By  the  term  definite  action,  as  used  in  this  chapter,  I  mean 
an  action  of  such  a  nature  that,  when  many  individuals  of 

^  Origin  of  Speries,  p.  17J:.  •  Ibid.  p.  175. 


330         Darwifif  and  after  Darwin, 


I        ( 


K 


>  I' 


ii' 


the  same  variety  are  exposed  during  several  generations  to 
any  change  in  their  physical  conditions  of  life,  a//,  or  nearly 
all^  the  individuals  arc  modified  in  the  same  manner.  A  new 
sub-variety  would  thus  be  produced  without  the  aid  of  selec- 
tion\'* 

As  an  example  of  the  special  instances  that  he  gives, 
I  may  quote  the  following  from  the  same  work  : — 

"  Each  of  the  endless  variations  which  we  see  in  the  plumage 
of  our  fowls  must  have  had  some  efficient  cause ;  and  if  the 
same  cause  were  to  act  uniformlv  during  a  long  series  of 
generations  on  many  individuals,  all  probably  would  be  modi- 
fied in  the  same  manner." 

And,  as  instances  of  his  more  general  statements  in  Chapter 
XXIII,  these  may  suffice : — 

"  The  direct  action  of  the  conditions  of  life,  whether  leading 
to  definite  or  indefinite  results,  is  a  totally  distinct  consider- 
ation from  the  efjfects   of  natural   selection The 

direct  and  definite  action  of  changed  conditions,  in  contra- 
distinction to  the  accumulation  of  indefinite  variations,  seems 
to  me  so  important  that  I  will  give  a  large  additional  body 
of  miscellaneous  facts'." 

Then,  after  giving  these  facts,  and  showing  how  in  the 
case  of  species  in  a  state  of  nature  it  is  often  impossible  to 
decide  how  much  we  are  to  attribute  to  natural  selection  and 
how  much  to  the  definite  action  of  changed  conditions,  he 
begins  his  general  summary  of  the  chapter  thus : — 

"  There  can  be  n j  doubt,  from  the  facts  given  in  the  early 
part  of  this  chapter,  that  extremely  slight  changes  in  the 
conditions  of  life  sometimes  act  in  a  definite  manner  on  our 
already  variable  don?esticatfcd  productions  [productions,  there- 
fore, with  regard  to  which  uniformity  and  "stability"  of 
modification  are  least  likely  to  arise] ;  and,  as  the  action 
of  changed  conditions  in  causing  general  or  indefinite  vari- 


*  Variation,  &c.,  vol.  ii.  p.  a6o. 


*  Ibid,  vol.ii.  p.  261. 


Appendix  II, 


331 


ability  is  accumulative,  so  it  may  be  with  their  definite  ac- 
tion. Hence  it  is  possible  that  great  and  definite  modifications 
of  structure  may  result  from  altered  conditions  acting  during 
a  long  series  of  generations.  In  some  few  instances  a  marked 
effect  has  been  produced  quickly  on  all,  or  nearly  ail,  the 
individuals  which  have  been  exposed  to  some  considerable 
change  of  climate,  food,  or  other  circumstance*." 

Once  more,  in  order  to  show  that  he  retained  these  views 
to  the  end  of  his  life,  I  may  quote  a  passage  from  the  second 
edition  of  tlie  Descent  of  Man,  which  is  the  latest  expression 
of  his  opinion  upon  these  points: — 

"  Each  of  the  endless  diversities  in  plumage,  which  we  see 
in  our  domesticated  birds,  is,  of  course,  the  result  of  some  de- 
finite cause ;  and  under  natural  and  more  uniform  conditions, 
some  one  tint,  assuming  that  it  was  in  no  way  injurious^  would 
almost  certainly  sooner  or  later  prevail.  The  free-inter- 
crossing of  the  many  individuals  belonging  to  the  same  species 
would  ultimately  tend  to  make  any  change  of  colour  thus  in- 
duced uniform  in  character.  ....  Can  we  believe  that  the 
very  slight  differences  in  tints  and  markings  between,  for  in- 
stance, the  female  black-grouse  and  red-grouse  serve  as  a 
protection  ?  Are  partridges  as  they  are  now  coloured,  better 
protected  than  if  they  had  resembled  quails  ?  Do  the  slight 
differences  between  the  females  of  the  common  pheasant,  the 
Japan  and  golden  pheasants,  serve  as  a  protection,  or  might 
not  their  plumage  have  been  interchanged  with  impunity  ? 
From  what  Mr.  Wallace  has  observed  of  the  habits  of  certain 
gallinaceous  birds  in  the  East,  he  thinks  that  such  slight 
differences  are  beneficial.  For  myself,  I  will  only  say,  I  am 
not  convinced"." 

Yet  "  convinced "  he  certainly  must  have  been  on  merely 
a  priori  grounds,  hi.d  he  countenanced  Mr.  Wallace's 
reasoning  from  the  general  theory  of  natural  selection ;  and 
the  fact  that  he  here  fails  to  be  convinced  even  by  "  what 
Mr.  Wallace  has  observed  of  the  habits  of  certain  gallinaceous 


Variation,  &c.,  vol.  ii.  p.  a  80. 


Descent  of  Man,  pp.  473-4. 


332         Darwifiy  and  after  Darwin, 


h 

"Ml, 

?3 


li  ;tft 


ft' 

h 


birds,"  appears  to  indicate  that  he  had  considered  the  question 
of  utility  with  special  reference  to  Mr.  Wallace's  opinion. 
That  opinion  was  then,  as  now,  the  avowed  result  of  a  theo- 
retical prepossession ;  and  this  prepossession,  as  the  above 
quotations  sufficiently  show,  was  expressly  repudiated  by 
Darwin. 

Lastly,  this  is  not  the  only  occasion  on  which  Darwin 
expressly  repudiates  Mr.  Wallace's  opinion  on  the  point 
in  question.  For  it  is  notorious  that  these  co-authors  of 
the  theory  of  natural  selection  have  expressed  divergent 
opinions  concerning  the  origin  by  natural  selection  of  the 
most  general  of  all  specific  characters— cross-sterility. 
Although  allowing  that  cross-sterility  between  allied  species 
may  be  of  adaptive  value  in  "  keeping  incipient  species  from 
blending,"  Darwin  persistently  refused  to  be  influenced  by 
Wallace's  belief  that  it  is  due  to  natural  selection ;  i.  e.  the 
belief  on  which  alone  can  be  founded  the  "  necessary  de- 
duction "  with  which  we  have  been  throughout  concerned. 


Note  A  to  Page  57. 


I  THINK  it  is  desirable  here  to  adduce  one  or  two  concrete 
illustrations  of  these  abstract  principles,  in  order  to  shov/  how, 
as  a  matter  of  fact,  the  structure  of  Weismann's  theory  is 
such  as  to  preclude  the  possibility  of  its  assumptions  being 
disproved— and  this  even  supposing  that  the  theory  is  false. 

At  first  sight  nothing  could  seem  more  conclusive  on  the 
side  of  Darwinian  or  Lamarckian  principles  than  are  the  facts 
of  hereditary  disease,  in  cases  where  the  disease  has  unques- 
tionably been  acquired  by  the  parents.  Take,  for  example, 
the  case  of  gout.  Here  there  is  no  suspicion  of  any  microbe 
being  concerned,  nor  is  there  any  question  about  the  fact 
of  the  disease  being  one  which  is  frequently  acquired  by 
certain  habits  of  life.  Now,  suppose  the  case  of  a  man  who 
in  middle  age  acquires  the  gout  by  these  habits  of  life— such 
as  insufficient  exercise,  over-sufficient  food,  and  free  indulgence 
in  wine.  His  son  inherits  the  gouty  diathesis,  and  even  though 
the  boy  may  have  the  fear  of  gout  before  his  eyes,  and  con- 
sequently avoid  over-eating  and  alcoholic  drinking,  &c.,  the 
disease  may  overtake  him  also.  Well,  the  natural  explanation 
of  all  this  is,  that  the  sins  of  the  fathers  descend  upon  the 
children  ;  that  gout  acquired  may  become  in  the  next  generation 
gout  transmitted.  But,  or,  the  other  hand,  the  school  of 
Weismann  will  maintain  that  the  reason  why  the  parent 
contracted  the  gout  was  because  he  had  a  congenital,  or 
"  blastogenetic,"  tendency  towards  that  disease— a  tendency 
which  may,  indeed,  have  been  intensified  by  his  habits  of 
life,  but  which,  in  so  far  as  thus  intensified,  was  not  trans- 
mitted to  his  offspring.    All  that  was  so  transmitted  was  the 


334        Darwin,  and  after  Darwin. 


1 

r'-' 
V' 


V 


congenital  tendency ;  and  all  that  is  proved  by  such  cases  as 
those  above  supposed,  where  the  offspring  of  gouty  parents 
become  gouty  notwithstanding  their  abstemious  habits,  is  that 
in  such  offspring  the  congenital  tendency  is  even  more  pro- 
nounced than  it  was  in  their  parents,  and  therefore  did  not 
require  so  much  inducement  in  the  way  of  unguarded  living 
to  bring  it  out.  Now,  here  again,  without  waiting  to  consider 
the  relative  probabilities  of  these  two  opposing  explanations, 
it  is  enough  for  the  purposes  of  the  illustration  to  remark 
that  it  is  obviously  impossible  to  disprove  either  by  means 
of  the  other,  or  by  any  class  of  facts  to  which  they  may 
severally  appeal. 

I  will  give  only  one  further  example  to  show  the  elusiveness 
of  Weismann's  theory,  and  the  consequent  impossibility  of 
finding  any  cases  in  nature  which  will  satisfy  the  conditions 
of  proof  which  the  theory  imposes.  In  one  of  his  papers 
Weismann  says  that  if  there  be  any  truth  in  the  Lamarckian 
doctrine  of  the  transmission  of  acquired  characters,  it  ought 
to  follow  that  the  human  infant  should  speak  by  instinct. 
For,  ever  since  man  became  human  he  has  presumably  been 
a  talking  animal :  at  any  rate  it  is  certain  that  he  has  been 
so  for  an  innumerable  number  of  generations.  Therefore,  by 
this  time  the  faculty  of  language  ought  to  have  been  so 
deeply  impressed  upon  the  psychology  of  the  species,  that 
there  ought  to  be  no  need  to  teach  the  young  child  its  use 
of  language ;  and  the  fact  that  there  is  such  need  is  taken 
by  Weismann  to  constitute  good  evidence  in  proof  of  the 
non-transmissibility  of  individually  acquired  characters.  Or, 
to  quote  his  own  words,  "  it  has  never  yet  been  found  that 
a  child  could  read  of  itself,  although  its  parents  had  throughout 
their  whole  lives  practised  this  art.  Not  even  are  our  children 
able  to  talk  of  their  own  accord ;  yet  not  only  have  their 
parents,  but,  more  than  that,  an  infinitely  long  line  of  ancestors 
have  never  ceased  to  drill  their  brains  and  to  perfect  their 
organs  of  speech.  .  .  .  From  this  alone  we  may  be  disposed 
to  doubt  whether  acquired  capabilities  in  the  true  sense  can 
ever  be  transmitted."  Well,  in  answer  to  this  particular  case, 
we  have  first  of  all  to  remark  that  the  construction  of  even 
the  simplest  language  is,  psychologically  considered,  a  matter 


Note  A, 


335 


of  such  enormous  complexity,  that  there  is  no  real  analogfy 
between  it  and  the  phenomena  of  instinct :  therefore  the  fact 
that  Lamarckian  principles  cannot  be  applied  to  the  case 
of  language  is  no  evidence  that  they  do  not  hold  good  as 
regards  instinct.  Secondly,  not  only  the  construction,  but 
still  more  the  use  of  language  is  quite  out  of  analogy  with 
all  the  phenomena  of  instinct ;  for,  in  order  to  use,  or  speak, 
a  language,  the  mind  must  already  be  that  of  a  thinking 
agent;  and  therefore  to  expect  that  lan.cjuage  should  be  in- 
stinctive is  tantamount  to  expecting  that  the  thought  of  which 
it  is  the  vehicle  should  be  instinctive — i.e.  that  human  parents 
should  transmit  the  whole  organization  of  their  own  intellectual 
experiences  to  their  unborn  children.  Thirdly,  even  neglecting 
these  considerations,  we  have  to  remember  that  language  has 
been  itself  the  produce  of  an  immensely  long  course  of  evolution; 
so  that  even  if  it  were  reasonable  to  expect  that  a  child 
should  speak  by  instinct  without  instruction,  it  would  be 
necessary  further  to  expect  that  the  child  should  begin  by 
speaking  in  some  score  or  two  of  unknown  tongues  before 
it  arrived  at  the  one  which  alone  its  parents  could  under- 
stand. Probably  these  considerations  are  enough  to  show 
how  absurd  is  the  suggestion  that  Darwinians  ought  to  expect 
children  to  speak  by  instinct.  But,  now,  although  it  is  for 
these  reasons  preposterous  under  any  theory  of  evolution  to 
expect  that  children  should  be  able  to  use  a  fully  developed 
language  without  instruction,  it  is  by  no  means  so  preposterous 
to  expect  that,  if  all  languages  present  any  one  simple  set 
of  features  in  common,  these  features  might  by  this  time 
have  grown  to  be  instinctive ;  for  these  simple  features,  being 
common  to  all  languages,  must  have  been  constantly  and 
forcibly  impressed  upon  the  structure  of  human  psychology 
throughout  an  innumerable  number  of  sequent  generations. 
Now,  there  is  only  one  set  of  features  common  to  all  languages  ; 
and  this  comprises  the  combinations  of  vowel  and  consonantal 
sounds,  which  go  to  constitute  what  we  know  as  articulate 
syllables.  And,  is  it  not  the  case  that  these  particular  features, 
thus  common  to  all  languages,  as  a  matter  of  fact  actually 
are  instinctive  ?  Long  before  a  young  child  is  able  to  under- 
stand the  meanings  of  any  words,  it  begins  to  babble  articulate 


336         DarwiUy  and  after  Darwin. 


p 

\ 

\  \ 

f 

h 

V 

J* 


•f 


Vt"M 


'<H 


I 


\m 


syllables ;  and  I  do  not  know  that  a  more  striking  fact  can 
be  adduced  at  the  present  stage  of  the  Weism  -«n  controversy 
than  is  this  fact  which  he  has  thus  himself  unconsciously 
suggested,  namely,  that  the  young  of  the  only  talking  animal 
should  be  alone  in  presenting— and  in  unmistakably  pre- 
senting—the instinct  of  articulation.  Well,  such  being  the 
state  of  matters  as  regards  this  particular  case,  in  the  course 
of  a  debate  which  was  held  at  the  Newcastle  meeting  of  the 
British  Association  upon  the  heredity  question,  I  presented 
this  case  as  I  present  it  now.  And  subsequently  I  was  met, 
as  I  expected  to  be  met,  by  its  being  said  that  after  all  the 
faculty  of  making  articulate  sounds  might  have  been  of  con- 
genital origin.  S'^eing  of  how  much  importance  this  faculty 
must  always  have  been  to  the  human  species,  it  may  very 
well  have  been  a  faculty  which  early  fell  under  the  sway 
of  natural  selection,  and  so  it  may  have  become  congenital. 
Now,  be  it  remembered,  I  am  only  adducing  this  case  in 
illustration  of  the  elusiveness  of  Weismann's  theory.  First 
of  all  he  selects  the  faculty  of  articulate  speech  to  argue  that 
it  is  a  faculty  which  ought  to  be  instinctive  if  acquired  char- 
acters ever  do  become  instinctive ;  and  so  good  does  he  deem 
it  as  a  test  case  between  the  two  theories,  that  he  szys  from 
it  alone  we  should  be  prepared  to  accept  the  doctrine  that 
acquired  characters  can  never  become  congenital.  Then,  when 
it  is  shown  that  the  only  element  in  articulate  speech  which 
possibly  could  have  become  congenital,  actually  has  become 
congenital,  the  answer  we  receive  is  a  direct  contradiction 
of  the  previous  argument  :  the  faculty  originally  selected  as 
representative  of  an  acquired  character  is  now  taken  as  repre- 
sentative of  a  congenital  one.  By  thus  playing  fast  and  loose 
Hrith  whatever  facts  the  followers  of  Darwin  may  adduce,  the 
followers  of  Weismann  bring  their  own  position  simply  to 
this : — All  characters  which  can  be  shown  to  be  inherited 
we  assume  to  be  congenital,  or  as  we  term  it,  "  blastogenetic," 
while  all  characters  which  can  be  shown  not  to  be  inherited, 
we  assume  to  be  acquired,  or  as  we  term  it,  "  somatogenetic  " — 
and  this  merely  on  the  ground  that  they  have  been  shown 
to  be  inherited  or  not  inherited  as  the  case  may  be.  Now, 
there   need   be  no  objection  to  such  assumptions,  provided 


Note  B. 


337 


they  are  recognized  as  assumptions ;  but  so  long  as  the  very 
question  in  debate  has  reference  to  their  validity  as  assumptions, 
it  is  closely  illogical  to  adduce  them  as  arguments.  And  this 
is  the  only  point  with  which  we  are  at  present  concerned. 


Note  B  to  Page  89. 


In  answer  to  this  illustration  as  previously  adduced  by  me, 
Mr.  Poulton  has  objected  that  the  benefit  arising  from  the 
peculiar  mode  of  stinging  in  question  is  a  benefit  conferred, 
not  on  the  insect  which  stings,  but  upon  its  progeny.  The 
point  of  the  illustration  however  has  no  reference  to  the 
maternal  instinct  (which  here,  as  elsewhere,  I  doubt  not  is 
due  to  natural  selection) ;  it  has  reference  only  to  the  particular 
instinct  of  selective  stinging,  which  here  ministers  to  the  pur- 
poses of  the  other  and  more  general  instinct  of  rearing  progeny. 
Given  then  the  maternal  instinct  of  stinging  prey  for  the  use 
of  progeny,  the  question  is — What  first  determined  the  ancestors 
of  the  Sphex  to  sting  their  prey  only  in  nine  particular  points  ? 
Darwin's  answer  to  this  question  is  as  follows : — 

*•  I  have  been  thinking  about  Pompilius  and  its  allies.  Please 
take  the  trouble  to  read  on  perforation  of  the  corolla  by  Bees,  p.  425 
of  my  'Cross-fertilization,'  to  end  of  chapter  Bees  show  so  much 
intelligence  in  their  acts,  that  it  seems  not  improbable  to  me  that  the 
progenitors  of  Pompilius  originally  stung  caterpillars  and  spiders,  'c., 
in  any  part  of  their  bodies,  and  then  observed  by  their  intelligence 
that  if  they  stung  them  in  one  particular  place,  as  between  certain 
segments  on  the  lower  side,  their  prey  was  at  once  paralyzed.  It 
does  not  seem  to  me  at  all  incredible  that  this  action  should  then 
become  instinctive,  i.  e.  memory  transmitted  from  one  generation 
to  another.  It  does  not  seem  necessary  to  suppose  that  when 
Pompilius  stung  its  prey  in  the  ganglion  it  intended  or  knew  that 
their  prey  would  keep  long  alive.  The  development  of  the  larvae 
may  have  been  subsequently  modified  in  relation  to  their  half- dead, 
instead  of  wholly  dead  prey ;  supposing  that  the  prey  was  at  first 
quite  killed,  which  would  have  required  much  stinging.  Turn  this 
over  in  your  mind,"  &c. 

II.  Z 


* '' 


338         Darwifiy  and  after  Darwin, 


V 


•hi 


H. 


Weismann,  on  the  other  hand,  can  only  suppose  that  this 
intensely  specialized  instinct  had  its  origin  in  fortuitous  varia- 
tions in  the  psychology  of  the  species.  But,  neglecting  the 
consideration  that,  in  order  to  become  fixed  as  an  instinct 
by  natural  selection,  the  particular  variation  required  must 
have  occurred  in  many  different  individuals,  not  only  in  the 
first,  but  also  in  the  sequent  generations,  the  chances  against 
its  occurring  only  once,  or  in  but  one  single  individual  case,  are 
many  thousands  if  not  millions  to  one. 


■i 

\S¥a 


\0 


■1  ! 


w 


m  I 


INDEX 


-M- 


Acceleration  and  retardation,  i6. 
Acquired   characters,  heredity  of, 

39.  103. 133-  ^     ^ 

Adaptation,  7,  13,  55>  62,  67,  71, 
159,  165;  of  species  and  of 
specific  characters,  166. 

Allen,  Mr.,  referred  to,  209. 

All-sufficiency  of  Natural  Selection, 
referred  to,  65,  95. 

Alone  with  the  Hairy  Ainu,  re- 
ferred to,  26. 

American  and  European  trees 
compared,  201. 

American  Journal  of  Science,  re- 
ferred to,  273. 

American  Naturalist,  referred  to, 

35.  58.  .       ^ 

Ammonites,  species  of,  254. 

Animal  Intelligence,  referred  to,  93. 

Animal  Life,  referred  to,  loi. 

Animal  Life  and  Intelligence,  re- 
ferred to,  33,  36. 

Apparent  Faradox  in  Mental 
Evolution^  referred  to,  90. 

Appendages  of  Normandy  and 
Irish  pigs,  188. 

Articulation  and  inheritance,  335. 

Artistic  faculties  of  man,  37. 

B. 

Babington, Prof., referred  to,  25a. 
Bach  MAN,  Dr.,  referred  to,  186. 
Bailby,  Prof,  referred  to,  127. 
Baker,  Mr.,  referred  to,  352. 


Balancing  of  brainless  frog,  78. 

Ball,  Mr.  Piatt,  referred  to,  3, 
95 ;  quoted,  50. 

Bateson,  Mr.  W.,  referred  to,  36. 

Beddard,  Mr.  F.,  referred  to, 
174. 

Bentham,  Mr.,  referred  to,  352. 

Birds,  diagnostic  characters  of, 
176;  of  Australia,  effect  of  cli- 
mate on,  a  10  ;  influence  of  food 
on,  318. 

Blastogenetic,  123,  343,  245,  250. 

Blending  of  adaptations,  67. 

Brain,  referred  to,  80. 

Broca,  Prof.,  referred  to,  64,  67, 

174.  318. 
Bronn,  Prof.,  referred  to,  174. 
Brooks,  Prof.,  referred  to,  14. 
Brown-S^quard,  referred  to,  104, 

123,  14a  ;  quoted,  104. 
Buckley,  Mr.,  referred  to,  147. 
BucKMAN,  Prof.  James,  referred 

to,  125. 
BucKMAN,  Prof.  S.  S.,  referred  to, 

24. 
Butler,  Mr.  A.  G.,  referred  to, 

354- 
Butler,  Mr.  Samuel,  referred  to, 

87. 

Butterfly,  seasonal  changes  of,  210; 

influence  of  food  on,  317. 

C. 

Carnivora,  instincts  of,  89. 
CARRii:RE,  M.  L.  A.,  referred  to, 
133. 

2 


340 


Index, 


u 


'Vv 


k 


Ml 


Cave  animals,  colour-changes  in, 

211. 

Cave  Fauna  of  North  America, 

quoted,  3ii. 
Cessation  of  Selection,   99,   199, 

312,  292. 

Characters,  adaptive  and  specific, 
159, 307;  specific  "uetoNs  aral 
Selection,  17  r. 

Charadriidae,  Geogr^:^  -''u.  ul  /  *'stri- 
bution  of  the   Fan,.!^y,  4.r.;<  i.'d, 

173. 
Chimpanzee,  counting  or,  31. 
Climate,  influence  of,  on  plants, 

aoo ;  on  animals,  209. 
Co-adaptation,  64. 
CvJCKERELL,   Prof.,    referred    to, 

218. 
Colour,  269. 
Colour-chaiijjes  in  butterflies,  310. 

in  cave  animals,  21 1. 
Colours  of  Animals,  referred  to, 

3^'-    .  .    . 

Congenital,  as  opposed  to  acquired 

characters,  134. 

Constancy  of  cliaracters  not  neces- 
sarily due  to  Natural  Selection, 
186. 

Contemporary  Review,  referred  to, 
60,  65,  95. 

Continuity  of  germ-plasm,  44,  61, 
133;  absolute  and  relative,  134, 

Contributions   to   the    Theory  of 

Natural  Selection,  referred  to,  2  ; 

quoted,  180. 
Cope,   Prof,  referred  to,  14,  15, 

20,  63,  256  ;  quoted,  16. 
Correlation,   171,   184,    211,    222, 

268. 
Costa,  M.,  quoted,  217. 
Cunningham,  Mr.  J.  T.,  quoted, 

103;  referred  to,  95,  122. 

D. 

Dall,  Prof.,  referred  to,  14. 

Darwin,  Charles,  referred  to, 
1-13,  20-22,  35,  44,  45,  51-53. 
56,  66,  67,  74,  87,  88,  93,  95, 
96-100,  149, 159, 160, 167,  173, 
174,   181-183,    187-191,    193, 


i95>  19S,  30o-ao3,  313-216, 
21H,  219,  226,  256,  261-265, 
268,  271,  277,  283,  287,  291, 
305-307,  .^'3-332,337;  quoted, 
iJ>  53,  66,  96,  181,  182,  i36- 
191,  193,  19s,  201,  202,  313- 
315,  261,  262,  265,  313-316, 
3>9-322,     324  32'5,     328-331, 

337- 
Darwin  et  ses  Pricurseurs  Fran- 

(ais,  referred  to,  234. 
Darwinian  Theory  of  the  Origin 

of  Species,  quoted,  254. 
Daiwinism,   quoted,  22,   27,  67, 

181,  182,    186,    189-191,    221, 

222,  235,  336,  352,  253,   369, 

270,   273,   313,    316;    referred 

to,  7,  12,  15,  20,  70. 
De  Candolle,  Prof.,  referred  to, 

206. 
Deep-sea  faunas,  212. 
Delbceuf,  referred  to,  224. 
Descent  of  Man,  quoted,  25,  322- 

324,  331. 
Development  of  the  Hard  Parts  of 

the  Mammalia,  referred  to,  14. 

De  Vries,  Prof.,  referred  to,  122, 
174. 

Dia)L;nostic  charactersof  birds,  1 76 ; 
Marsupials,  178. 

Divergent  Evolution  through 
Cumulative  Segregation,  quoted, 
324. 

Dixon,  Mr.  Charles,  referred  to, 
174;  quoted,  177,  223. 

Doctrine  of  Descent  and  Daruiin- 
ism,  quoted,  360. 

Dogs,  scratching,  reflex  of,  80 ; 
shaking  off  water,  84 ;  trans- 
plantation of  ovaries,  143. 

DoRFMElSTER,  Dr.,  referred  to. 


311. 


96; 


Ducks,    use-inheritance    in, 
losing  true  plumage,  187. 
DUPUY,  Dr.,  referred  to,  105. 
Dyer,   Mr.    Thistleton,    quoted, 

325,327- 

E. 

Effect  of  External  Influences  upon 
Development,  referred  to,  66,95. 


Index, 


34' 


Effects  of  Use  and  Disuse,  quoted, 
50. 

ElMKR,  Prof.,  referred  to,  14,  174, 
217. 

Enti'tnologicnl  Society,  Trans,  of, 
quoted,  211;  referred  to,  217. 

Epilepsy  of  .iT'iinea-jiig';,  104. 

Essays  on  Jlctniify,  quc)tcd,  56, 
91,  97,  107,  152;  referred  to, 
12,  36.  65,  105.  no. 

EtrDEs-DKSLONGCHAMPS,  M.,  re- 
ferred to,  188. 

European  and  American  trees, 
compared,  201. 

Everest,  Kev.  E.,  quoted,  213. 

Evolution  without  Natural  Selec- 
tion, quoted,  177. 

Examination  of  IVeismann'sm, 
referred  to,  .^9-42,  44,  100,  122, 

123.  I34»  I3^>.  ip.'^-HO.  i.^'J- 
Experivients   in   Pangenesis^  re- 
ferred to,  145. 

F. 

Fabre,  M.,  referred  to,  88. 

Factors  of  organic  evolution : 
Natuial  Seleclion,  2,  5,  6  ;  use- 
inlieiitance,  3,  11. 

Factors  of  Organic  Evolution,  re- 
ferred to,  8, 

Faculties  and  organs,  29. 

Fertility,  229. 

Flat-fish,  Mr.  Cunninghain  on, 
103. 

Floral  Structures,  referred  to,  19. 

FocKE,  Dr.,  referred  to,  174. 

Fonctions  du  Ce>  vcau,  referred  to, 
IC9. 

Food,  influence  of,  217. 

Foot,  of  man,  23. 

Frog,  brainless,  balancing  of,  78. 


Galton,  Mr.  Francis,  referred  to, 

40  48,  100,  103,  1.34- '39.  '45. 

146,152,154,156,300,303-3:5; 

quoted,  46,  100. 
Gangrene,  effects  of,  51,  105. 
Gardeners  C7i!;w/?V/«,  quoted,  127. 
Gart.nkr.  Dr.,  referred  to,  206. 
Geddes,  Prof.,  referred  to,  15,  20, 

174. 


Gcmniules,  47, 145,  T55. 
Genera  and  s[)ecies,  261. 
(lerm-plasiu    and    JStirp,  40;   and 

pant;c!.esis,  42;  isolation  of,  137; 

stability  of,  243, 
Gertn-flasm,  releirtd  to,  128. 
GlAKl),  Prof..  leferred  to,  14,  174. 
Giralie,  co-adaptalion  in,  64. 
GoLTZ,  i'rof.,  referred  to,  80,  84. 
(JoULU,  .Mr.,  relerrcd  to,  210. 
Graftr-liybiidization,  143. 
Growth,  laws  of,   22a,  226,  348, 

270,  321. 
Guinea  pigs,  epilepsy  of,  104. 
GULICK,  Mr. .  refei  red  to,  1 74     ;"i, 

260,  271  ;    quoted,  224,  .'/.;. 
Cute  und  schlechte  Arten,    -lolc' 

ao3. 

H. 

ITnbit,  henditary,  87. 

Habit  and  Intelligence,  r  loted,  2  2  5 . 

Hanfi,  of  man,  24. 

Handbook  of  British  Flo.  a, .  aferred 

to,  252. 
IIaycraft,  Prof.,  referred  to,  80. 
II  E.VPK.  Mr.  Waller,  referred  to,  147. 
HkNSLOW,  Piof   George,  referred 

to,  18-20,   127-132,   174,   20-<  ; 

quoted,  19,  130,  131. 
Heredity,  problems  of,  39. 
H EKING,  Prof.,  I ef erred  to,  87. 
Hewitt,  Mr.,  referred  to,  187. 
Him-,  Prof.  Leonard,  quoted,  132. 
llAECKEL,  Prof.,  referred  to,  174, 

260,  282. 
Hoi  I  MAN.N,  Dr.,  referred  to,  123, 

2  So. 
Horse,  call<;sities  of,  265. 
Hu.xi.EV,  Prof.  T.  H.,  re'erred  to, 

167-170,    1 85,    256,    2:5,    283, 

^107-312;  quf)ted,  307  309. 
Huxkyan  doetrine  of  species,  l*')7. 
PlYAT'l',  Prof.,  referred  to,  14,  15. 
llymenoptera,  scjcial,  9a. 

I. 

htade<]uacy  of  Natural  Selection, 

refeircd  to,  65,  95. 
liiionsistencie'i  of  Utililariaiiism  as 

the  Exclusive  'theory  of  Uiganie 

/'Evolution,  (juoted.  273. 


li: 


342 


Index, 


i; 

IN 


Inrlifferent    characters,    171,    185, 

20S,  247. 
Iii>ects,  insliiiclb  of,  9). 
Instability   of  Useless    characters, 

186. 
Instinct  ami  hereditary  habit,  87 ; 

of  Si<aex,  88  ;  of  carnivora,  89  ; 

of  man,  <S9 ;    Pruf.  VVeisinaun's 

views  on,  90  ;   of  insects,  91. 
Intcrcroj^sin.,  67-71. 
Isolation,  22,'',  ^/ j^^. 

J. 

JoRUAN,  Dr.,  referred  to,  206,352. 

K. 

Knryokinesis,  140. 

Kkrner,  Prof.,  referred  to,   174, 

202-2o(*,   231,  239,   260,    282; 

quoted,  203. 
Koch,  Dr.,  referred  to,  217, 
KdixiKKR,  Prof.,  referred  to,  174. 

L. 

Lamarck,  referred  to,  9-15. 
Lamarokism,  9,  61,  113. 
Landor,  a.  H.  Savage,  referred  to, 

26. 
Language  and  Weismannism,  334. 
Lankester,   Prof.  Ray,   quoted, 

245,  299  ;  referred  to,  305. 
Lesage,  ^I.,  referred  to,  126. 
Li/e  and  Letters  of  Charles  Darwin, 

quoted,  319,  320  ;  leferred  to,  1 1. 
Luciani,  referred  to,  109. 

M. 

Making  of  I'lorvers,  referred  to,  19. 

Manual  of  British  Botany,  re- 
ferred to,  252 

Manual  of  Dental  Anatomy,  figure 
from,  267. 

Marsupials,  diagnostic  characters 
of.  17'?. 

■Materials  for  the  Study  of  p'aria- 
tion.  refened  to,  36. 

Mkehan,  Mr.,  referred  to,  201. 

Mr.LDOLA,  Prof.,  referred  to,  68. 

Mental  Evolution  in  Animals,  re- 
ferred to,  25,  88,  Sy,  92. 


On  Truth,  referred  to,  217. 
Oiang-uian,  teeth  of,  267. 
Mental  Evolution  in  Man,  referred 

10,  31. 
Merrifiei.d,  Mr.,  referred  to,  an. 
Mice,  mutilation  of  tails  of,  148. 
MlVART,  Prof.  St.  George,  referred 

to,  4,  174,  217. 
Monstrosity,  in   turkeys,  181  ;    in 

cattle,  196. 
Morgan,    Prof.    Lloyd,   referred 

to,  33,  36.  174.  271,  300  30.^; 

quoted,  300,  303. 
MobEi.EY,  Prof.,  leiLired  to,  26. 
MuRPliY,  Mr.  J.  J.,    lelerred    to, 

224. 
Mutilations,  inheritance  of,  53,  148 

N. 

Nagei.I,   Prof.,  referred  to,   174, 

206,  318. 
Naked  skin  ol  man,  25. 
Nathusius,  referred  to,  iSS. 
Natural  Selection,  range  of,  a,  5, 

51,  62,  9a  ;   a  theory  of  species, 

161, 169;  and  cave  animals,  211 ; 

and  Porto  Santo  rabbits,  214 
Natural  Selection    and    Tropical 

Nat  lire,  quoted,  33. 
Natwal  Science,  quoted,  104. 
iVa/««, quoted,  132,  323,  345,  ^99, 

325  ;  referred  to,  68,  98,  3i8. 
Neo-Darwinian  school,  10,  61. 
Neo-Lamarckian  school,  13,62,63. 
Niuer  Beitrag  zum  gcologischcn 

Betveis       der       Darwin  schen 

'Jheorie,  quoted,  254. 
Neuter  Insects   and  Danvinism, 

referred  to,  95. 
Neuter  Insects  and  Lamarckism, 

referred  to,  05. 
Neuters  of  hymenopterous  insects, 

92. 
Newman,  Car.-linal,  referred  to,  3o. 
Niata  cattle,  191. 

O. 

Orersteiner,   Dr.,  referred   to, 

105,  io(3. 
Oesicrreichische  medicinische  Jahr- 
biicher,  referred  to,  105. 


Index, 


343 


Organic   Evolution,    referred    to, 

217. 

Origin  of  the  lit  test,  quoted,  16; 
rcleir((l  to,   14. 

Originc  des  /'lantes  Domcstiqiies. 
dimoiitr^e  par  la  culture  du 
A'a.tis  sauvage,  referred  to,  i  J3. 

Origin  0/ .Sex.  referred  'o,  17. 

Origin  of  species, quoted,  'J,,  4,  iSi, 
1S2,  )S6,  188,190, 2^)1,  262,  3''>5, 
321,  322,  335,326,329  ;  rcferrcil 
t",  ^'7,  i59»  327,  286. 

OsiujRN,  Prof,  referred  to,  14,  58, 

Owen,  Sir   Richard,  referred   to, 

Oxen,  skidls  of,  compared,  193. 
Oysters,  change  of,  317. 

P. 

Packard,  Prof.,  referred  to,  14, 

213. 
Panj^eiiesis,  11,  42. 
Panmixia,  97,  213,  391. 
Parsimony,  law  of,  51. 
Parsnips,  vaiiation  of,  125. 
Pascoe,    Mr.,   referred    to,    174; 

quoted,  254. 
Pkrrikr,  Prof.,   referred   to,   14, 

93  9.S- 

Pktkr,  Dr.,  referred  to,  206. 

Pfrfkrr,  llerr,  referred  to,  15. 

rfliigers  Archiv.  referred  to,  80. 

Philosophical  Transactions,  re- 
ferred lo,  103. 

Physiological  Selection,  refeire<I  to, 

'^7'  .'.o7>  .^»'.'»  324;  quoted,  18.S, 

308. 
Pickard  Camhridgk,   Rev.    ().. 

quoted,  221. 
Tic,',  old  Iiish,  188. 
I'lants,   influence   of  climate    on, 

122  207. 
Porto  Sanlo  rahbits,  214. 
PjULTOn,  E.  B.,  referred  to,  3^), 

2  17-337- 
Presidential  Address  to  the  Bi  istol 

A  at malists Society, ;  89i,quotc«l, 

30U.  3-3- 
I  roccedings  of  the  Royal  Society, 

referred  to,   145,   147;    quoted, 
307- 


I'roteetive  resemMance,  1i. 
Protrusion  of  eytLiall,  in  epileptic 
guinea-pigs,  1 1 1. 


QUAiREiAGlis,   M.,    referred   to, 

334- 

R. 

Rabbits,  and  u^e-inheritanoe.  96; 
transplaiit.TliDn  of  ovaiies,  143; 
Poito  Santo,  214. 

Rnciish,  vaiiation  of,  123. 

Rat>.  scratching;,  reflex  of,  81. 

Kaupen  und  Schincttcrlinge  der 
ll'etterau,  ref  rred  to,  21 :. 

Reflex  action  and  use-inheritance, 
64-S7. 

Kcjovidcr  to  /Vof.  U  eisniann,  ro- 
le rred  to    9;,. 

Reversal  ol  selection,  loi,  292. 

Kevue  Liinirale  de  JJotanie,  referred 
to,  120. 

RK;nARl)S()N,  referred  to,  188. 

lva)UX,  Prof,  referred  to,  29:-). 

Rudiments,  294. 

Ryder,  Prof.,  referred  to,  14. 

S. 

Sachs,  Prof,,  referred  to,  15,  174. 
"Sally,"  counting  of,  31. 
Saukrman.n,  Dr..  relerred  to,  318. 
SCMAKER.  I'rof..  refei red  tn,  14.-, 
Schmetterliiii^e  des  Siidwestlic/ieH 

Dculschlands,  referred  to,  217. 
Schmidt,  Dr.  Oscar,  quoted,  j6o 
S.hc'ols  of  Evoluticmisis,  12  -20. 
Scori',  Prof.,  referred  to,  63. 
Scratehini,\  rellcx,  in  do^s,  No  ;  in 

rats,  81. 
Seasonal    changes    of    buiterliies, 

210. 
SEEliniiM.     Mr.     Henry,    quoted, 

I  73  ;  ref  I  led  to    i  74. 
Selection,  cessation   d,  99,    2^2; 

reversal  of,  101,  292. 

sexual,  i\C)  et  se^j. 

Selective  value,  73. 
Self-adaptation.  18. 
Skmi'ER,  Prni.  Knrl,  referred  to, 

101. 
Sexual  selection,  219  et  seq. 


344 


Index. 


•31 

I] 


'1: 

«* 
It  n 


h 


f 


Soli*.  I  if;ment  of,  104. 
aomituyonclic  and  somatoplasm, 

'2.?,  137.  '55,  243  349. 
Some  Laws  of  //ereJity,  rtfcrrcd 

to,  34. 
SiKcics,  stress  laid  on  origin  of, 

159;  neces^Miily  due  to  natural 

scleclion,  i'')8. 

definitions  of,  339. 

Si  RNCKR,  Ilerboit,  lekried  to,  8, 

O^-OS,  95. 
Sphox,  instincts  of,  88,  3.',7. 
Stehhing,  Rev.  T.  R.,  (juoted,  25. 
Sterility,  8. 

Stirp  and  ecim- plasm,  40,  47,  138. 
Stnii^'i^Ufir  Existence  between  the 

flirts  of  an  Organism,  referri  d 

to,  399. 

T. 
Theory  of  Heredity,  referred   to, 

40)47,  '37,  154;  quoted, 46,  47. 
Thomas,  Mr.  Oilfield,  referred  to, 

178. 
Thomson,  J.  A.,  referred  to,  15. 
Todd,  J.  E.,  referred  to,  35. 
Tomes,  Mr.,  referred  to,  267. 
Trai'slusion  of  blood  in  rabbits, 

,145- 
Transplantation     of    ovaries     in 

rabbits,  143,  147. 
Treis.   comparison   of    European 

and  Ameiican,  30i. 
Turkey,  tuft  of  hair  of,  181  ;  losing 

metallic  tints,  186. 

U 

Usr-inlieritancf,  3.49,  77,95.  151. 

Utility,  law  of,  8,  20,  1 59  ;  uni- 
versality of,  166;  of  specific 
characters,  173;  of  specific 
characters  in  birds,  1 76 ;  of 
specific  characters  in  Mammals, 
178. 

V. 

Variati  :i  of  Animals  and  Plants 
under  Domestication,  qaoicd,  3, 


4.  53.  ^'5,  9^.  '^7.  »89,  191, 

»03.  '95.  313  3i6,  330,  331. 
Varieiics,  climatic,  3a8, 
Vcsiif,'ialclarncter8,  171,  184,  361, 

394. 
ViNKS,  Prof.,  referred  to,  397. 
Vitality,    plumes  of  birds  due  to 

surplus,  370,  35. 
Voice,  ol  man,  35. 

W. 

Wagner,  Morit/,  rcferrc'l  to,  317, 
Wallace.  Mr.  A.  K.,  referred  to, 
3,  6,  9,  II,  15,  30  7.5,  50,66- 
70,  167,  169,  173-175,  180-19S, 
310,  318-337,335-337,  a52,3.s6, 
35S,  263  278,  385,  313-323, 
3^8,  331,  333;  quoted,  23  34, 
37,    67,   180-182,   185,  186,  I()0, 

191,  331-333,    235,    336,    369, 

27.1.  .^13. 

Wallaccan  doctrine  of  species,  167, 
169. 

Weismann,  Prof.,  referred  to,  a, 
7,  9,  13,  13,  39-60,  65,  66,  90- 
105,  113,  138,  134-142.  148, 
149,  151,  152,  155,  156, 
341,  343,  244,  346,  279, 
391,  394,  397,  3(;8,  300, 
338;  quoted,  56,  91,  97. 
343,  244,  297. 

Weisraannism,  diagram  of  con- 
stituent theories,  43,  136;  elu- 
siveness  of,  334. 

Weismannism  once  more,  referred 
to,  66,  05. 

WeliiY,  Hon.  Lady,  leferred  to, 
90 

Westphal,  Prof.,  referred  to,  105, 
107. 

Withdrawal  of  foot  by  reflex  action, 

WUrtenbep.ger,  Dr.,  referred  to, 
354- 

Y. 

Yarrei.t,.  Mr.,  referred  to,  186. 


173. 
280, 

3i'i 
152, 


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